Nginx installation on Linux server

Step by step Nginx installation on YUM or APT based Linux servers. Know about configuration files, log files, and directory listing in Nginx.

Nginx is a popular web server and preferred over Apache. Many websites and blogs today run on Nginx webserver. In this article, we are going to see how to install Nginx in Linux.

Nginx Installation

Nginx is available for install in EPEL repositories for YUM based Linux systems and in default repositories of APT (Debian) based systems. Depending on your system type install the Nginx package. Sample outputs below :

# yum install nginx
Loaded plugins: amazon-id, rhui-lb, search-disabled-repos, security
Setting up Install Process
epel/metalink                                                                                                                         | 4.4 kB     00:00
epel                                                                                                                                  | 4.3 kB     00:00
https://mirrors.tuna.tsinghua.edu.cn/epel/6/x86_64/repodata/repomd.xml: [Errno -1] repomd.xml does not match metalink for epel
Trying other mirror.
epel                                                                                                                                  | 4.3 kB     00:00
rhui-REGION-client-config-server-6                                                                                                    | 2.9 kB     00:00
rhui-REGION-rhel-server-releases                                                                                                      | 3.5 kB     00:00
rhui-REGION-rhel-server-releases-optional                                                                                             | 3.5 kB     00:00
rhui-REGION-rhel-server-rh-common                                                                                                     | 3.8 kB     00:00
Resolving Dependencies
--> Running transaction check
---> Package nginx.x86_64 0:1.10.2-1.el6 will be installed
--> Processing Dependency: nginx-filesystem = 1.10.2-1.el6 for package: nginx-1.10.2-1.el6.x86_64
--> Processing Dependency: nginx-all-modules = 1.10.2-1.el6 for package: nginx-1.10.2-1.el6.x86_64
--> Processing Dependency: nginx-filesystem for package: nginx-1.10.2-1.el6.x86_64
--> Running transaction check
---> Package nginx-all-modules.noarch 0:1.10.2-1.el6 will be installed
--> Processing Dependency: nginx-mod-stream = 1.10.2-1.el6 for package: nginx-all-modules-1.10.2-1.el6.noarch
--> Processing Dependency: nginx-mod-mail = 1.10.2-1.el6 for package: nginx-all-modules-1.10.2-1.el6.noarch
--> Processing Dependency: nginx-mod-http-xslt-filter = 1.10.2-1.el6 for package: nginx-all-modules-1.10.2-1.el6.noarch
--> Processing Dependency: nginx-mod-http-perl = 1.10.2-1.el6 for package: nginx-all-modules-1.10.2-1.el6.noarch
--> Processing Dependency: nginx-mod-http-image-filter = 1.10.2-1.el6 for package: nginx-all-modules-1.10.2-1.el6.noarch
--> Processing Dependency: nginx-mod-http-geoip = 1.10.2-1.el6 for package: nginx-all-modules-1.10.2-1.el6.noarch
---> Package nginx-filesystem.noarch 0:1.10.2-1.el6 will be installed
--> Running transaction check
---> Package nginx-mod-http-geoip.x86_64 0:1.10.2-1.el6 will be installed
--> Processing Dependency: GeoIP for package: nginx-mod-http-geoip-1.10.2-1.el6.x86_64
--> Processing Dependency: libGeoIP.so.1()(64bit) for package: nginx-mod-http-geoip-1.10.2-1.el6.x86_64
---> Package nginx-mod-http-image-filter.x86_64 0:1.10.2-1.el6 will be installed
--> Processing Dependency: gd for package: nginx-mod-http-image-filter-1.10.2-1.el6.x86_64
--> Processing Dependency: libgd.so.2()(64bit) for package: nginx-mod-http-image-filter-1.10.2-1.el6.x86_64
---> Package nginx-mod-http-perl.x86_64 0:1.10.2-1.el6 will be installed
---> Package nginx-mod-http-xslt-filter.x86_64 0:1.10.2-1.el6 will be installed
---> Package nginx-mod-mail.x86_64 0:1.10.2-1.el6 will be installed
---> Package nginx-mod-stream.x86_64 0:1.10.2-1.el6 will be installed
--> Running transaction check
---> Package GeoIP.x86_64 0:1.6.5-1.el6 will be installed
--> Processing Dependency: geoipupdate for package: GeoIP-1.6.5-1.el6.x86_64
--> Processing Dependency: GeoIP-data for package: GeoIP-1.6.5-1.el6.x86_64
---> Package gd.x86_64 0:2.0.35-11.el6 will be installed
--> Processing Dependency: libXpm.so.4()(64bit) for package: gd-2.0.35-11.el6.x86_64
--> Running transaction check
---> Package GeoIP-GeoLite-data.noarch 0:2017.01-1.el6 will be installed
--> Processing Dependency: GeoIP-GeoLite-data-extra = 2017.01-1.el6 for package: GeoIP-GeoLite-data-2017.01-1.el6.noarch
---> Package geoipupdate.x86_64 0:2.2.1-2.el6 will be installed
---> Package libXpm.x86_64 0:3.5.10-2.el6 will be installed
--> Running transaction check
---> Package GeoIP-GeoLite-data-extra.noarch 0:2017.01-1.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

=============================================================================================================================================================
 Package                                      Arch                    Version                        Repository                                         Size
=============================================================================================================================================================
Installing:
 nginx                                        x86_64                  1.10.2-1.el6                   epel                                              462 k
Installing for dependencies:
 GeoIP                                        x86_64                  1.6.5-1.el6                    epel                                              113 k
 GeoIP-GeoLite-data                           noarch                  2017.01-1.el6                  epel                                              468 k
 GeoIP-GeoLite-data-extra                     noarch                  2017.01-1.el6                  epel                                               23 M
 gd                                           x86_64                  2.0.35-11.el6                  rhui-REGION-rhel-server-releases                  142 k
 geoipupdate                                  x86_64                  2.2.1-2.el6                    epel                                               28 k
 libXpm                                       x86_64                  3.5.10-2.el6                   rhui-REGION-rhel-server-releases                   51 k
 nginx-all-modules                            noarch                  1.10.2-1.el6                   epel                                              7.7 k
 nginx-filesystem                             noarch                  1.10.2-1.el6                   epel                                              8.5 k
 nginx-mod-http-geoip                         x86_64                  1.10.2-1.el6                   epel                                               14 k
 nginx-mod-http-image-filter                  x86_64                  1.10.2-1.el6                   epel                                               16 k
 nginx-mod-http-perl                          x86_64                  1.10.2-1.el6                   epel                                               26 k
 nginx-mod-http-xslt-filter                   x86_64                  1.10.2-1.el6                   epel                                               16 k
 nginx-mod-mail                               x86_64                  1.10.2-1.el6                   epel                                               43 k
 nginx-mod-stream                             x86_64                  1.10.2-1.el6                   epel                                               36 k

Transaction Summary
=============================================================================================================================================================
Install      15 Package(s)

Total download size: 24 M
Installed size: 49 M
Is this ok [y/N]: y
Downloading Packages:
(1/15): GeoIP-1.6.5-1.el6.x86_64.rpm                                                                                                  | 113 kB     00:00
(2/15): GeoIP-GeoLite-data-2017.01-1.el6.noarch.rpm                                                                                   | 468 kB     00:00
(3/15): GeoIP-GeoLite-data-extra-2017.01-1.el6.noarch.rpm                                                                             |  23 MB     00:01
(4/15): gd-2.0.35-11.el6.x86_64.rpm                                                                                                   | 142 kB     00:00
(5/15): geoipupdate-2.2.1-2.el6.x86_64.rpm                                                                                            |  28 kB     00:00
(6/15): libXpm-3.5.10-2.el6.x86_64.rpm                                                                                                |  51 kB     00:00
(7/15): nginx-1.10.2-1.el6.x86_64.rpm                                                                                                 | 462 kB     00:00
(8/15): nginx-all-modules-1.10.2-1.el6.noarch.rpm                                                                                     | 7.7 kB     00:00
(9/15): nginx-filesystem-1.10.2-1.el6.noarch.rpm                                                                                      | 8.5 kB     00:00
(10/15): nginx-mod-http-geoip-1.10.2-1.el6.x86_64.rpm                                                                                 |  14 kB     00:00
(11/15): nginx-mod-http-image-filter-1.10.2-1.el6.x86_64.rpm                                                                          |  16 kB     00:00
(12/15): nginx-mod-http-perl-1.10.2-1.el6.x86_64.rpm                                                                                  |  26 kB     00:00
(13/15): nginx-mod-http-xslt-filter-1.10.2-1.el6.x86_64.rpm                                                                           |  16 kB     00:00
(14/15): nginx-mod-mail-1.10.2-1.el6.x86_64.rpm                                                                                       |  43 kB     00:00
(15/15): nginx-mod-stream-1.10.2-1.el6.x86_64.rpm                                                                                     |  36 kB     00:00
-------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                        6.1 MB/s |  24 MB     00:03
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : GeoIP-GeoLite-data-extra-2017.01-1.el6.noarch                                                                                            1/15
  Installing : GeoIP-GeoLite-data-2017.01-1.el6.noarch                                                                                                  2/15
  Installing : nginx-filesystem-1.10.2-1.el6.noarch                                                                                                     3/15
  Installing : geoipupdate-2.2.1-2.el6.x86_64                                                                                                           4/15
  Installing : GeoIP-1.6.5-1.el6.x86_64                                                                                                                 5/15
  Installing : libXpm-3.5.10-2.el6.x86_64                                                                                                               6/15
  Installing : gd-2.0.35-11.el6.x86_64                                                                                                                  7/15
  Installing : nginx-mod-http-geoip-1.10.2-1.el6.x86_64                                                                                                 8/15
  Installing : nginx-mod-stream-1.10.2-1.el6.x86_64                                                                                                     9/15
  Installing : nginx-mod-http-perl-1.10.2-1.el6.x86_64                                                                                                 10/15
  Installing : nginx-mod-http-image-filter-1.10.2-1.el6.x86_64                                                                                         11/15
  Installing : nginx-mod-http-xslt-filter-1.10.2-1.el6.x86_64                                                                                          12/15
  Installing : nginx-1.10.2-1.el6.x86_64                                                                                                               13/15
  Installing : nginx-mod-mail-1.10.2-1.el6.x86_64                                                                                                      14/15
  Installing : nginx-all-modules-1.10.2-1.el6.noarch                                                                                                   15/15
  Verifying  : nginx-mod-mail-1.10.2-1.el6.x86_64                                                                                                       1/15
  Verifying  : GeoIP-1.6.5-1.el6.x86_64                                                                                                                 2/15
  Verifying  : nginx-mod-http-geoip-1.10.2-1.el6.x86_64                                                                                                 3/15
  Verifying  : libXpm-3.5.10-2.el6.x86_64                                                                                                               4/15
  Verifying  : nginx-mod-stream-1.10.2-1.el6.x86_64                                                                                                     5/15
  Verifying  : nginx-all-modules-1.10.2-1.el6.noarch                                                                                                    6/15
  Verifying  : GeoIP-GeoLite-data-2017.01-1.el6.noarch                                                                                                  7/15
  Verifying  : nginx-mod-http-perl-1.10.2-1.el6.x86_64                                                                                                  8/15
  Verifying  : nginx-mod-http-image-filter-1.10.2-1.el6.x86_64                                                                                          9/15
  Verifying  : nginx-1.10.2-1.el6.x86_64                                                                                                               10/15
  Verifying  : geoipupdate-2.2.1-2.el6.x86_64                                                                                                          11/15
  Verifying  : GeoIP-GeoLite-data-extra-2017.01-1.el6.noarch                                                                                           12/15
  Verifying  : nginx-filesystem-1.10.2-1.el6.noarch                                                                                                    13/15
  Verifying  : gd-2.0.35-11.el6.x86_64                                                                                                                 14/15
  Verifying  : nginx-mod-http-xslt-filter-1.10.2-1.el6.x86_64                                                                                          15/15

Installed:
  nginx.x86_64 0:1.10.2-1.el6

Dependency Installed:
  GeoIP.x86_64 0:1.6.5-1.el6                             GeoIP-GeoLite-data.noarch 0:2017.01-1.el6      GeoIP-GeoLite-data-extra.noarch 0:2017.01-1.el6
  gd.x86_64 0:2.0.35-11.el6                              geoipupdate.x86_64 0:2.2.1-2.el6               libXpm.x86_64 0:3.5.10-2.el6
  nginx-all-modules.noarch 0:1.10.2-1.el6                nginx-filesystem.noarch 0:1.10.2-1.el6         nginx-mod-http-geoip.x86_64 0:1.10.2-1.el6
  nginx-mod-http-image-filter.x86_64 0:1.10.2-1.el6      nginx-mod-http-perl.x86_64 0:1.10.2-1.el6      nginx-mod-http-xslt-filter.x86_64 0:1.10.2-1.el6
  nginx-mod-mail.x86_64 0:1.10.2-1.el6                   nginx-mod-stream.x86_64 0:1.10.2-1.el6

Complete!

# apt-get install nginx
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-4.4.0-59 linux-headers-4.4.0-59-generic linux-headers-4.4.0-66 linux-headers-4.4.0-66-generic linux-image-4.4.0-59-generic
  linux-image-4.4.0-66-generic
Use 'apt autoremove' to remove them.
The following additional packages will be installed:
  fontconfig-config fonts-dejavu-core libfontconfig1 libgd3 libjbig0 libjpeg-turbo8 libjpeg8 libtiff5 libvpx3 libxpm4 libxslt1.1 nginx-common nginx-core
Suggested packages:
  libgd-tools fcgiwrap nginx-doc ssl-cert
The following NEW packages will be installed:
  fontconfig-config fonts-dejavu-core libfontconfig1 libgd3 libjbig0 libjpeg-turbo8 libjpeg8 libtiff5 libvpx3 libxpm4 libxslt1.1 nginx nginx-common
  nginx-core
0 upgraded, 14 newly installed, 0 to remove and 64 not upgraded.
Need to get 2,999 kB of archives.
After this operation, 9,781 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 libjpeg-turbo8 amd64 1.4.2-0ubuntu3 [111 kB]
Get:2 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 libjbig0 amd64 2.1-3.1 [26.6 kB]
Get:3 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 fonts-dejavu-core all 2.35-1 [1,039 kB]
Get:4 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 fontconfig-config all 2.11.94-0ubuntu1.1 [49.9 kB]
Get:5 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 libfontconfig1 amd64 2.11.94-0ubuntu1.1 [131 kB]
Get:6 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 libjpeg8 amd64 8c-2ubuntu8 [2,194 B]
Get:7 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 libtiff5 amd64 4.0.6-1ubuntu0.1 [146 kB]
Get:8 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 libvpx3 amd64 1.5.0-2ubuntu1 [732 kB]
Get:9 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 libxpm4 amd64 1:3.5.11-1ubuntu0.16.04.1 [33.8 kB]
Get:10 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 libgd3 amd64 2.1.1-4ubuntu0.16.04.6 [126 kB]
Get:11 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 libxslt1.1 amd64 1.1.28-2.1 [145 kB]
Get:12 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 nginx-common all 1.10.0-0ubuntu0.16.04.4 [26.6 kB]
Get:13 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 nginx-core amd64 1.10.0-0ubuntu0.16.04.4 [428 kB]
Get:14 http://ap-south-1.ec2.archive.ubuntu.com/ubuntu xenial-updates/main amd64 nginx all 1.10.0-0ubuntu0.16.04.4 [3,498 B]
Fetched 2,999 kB in 2s (1,135 kB/s)
Preconfiguring packages ...
Selecting previously unselected package libjpeg-turbo8:amd64.
(Reading database ... 138589 files and directories currently installed.)
Preparing to unpack .../libjpeg-turbo8_1.4.2-0ubuntu3_amd64.deb ...
Unpacking libjpeg-turbo8:amd64 (1.4.2-0ubuntu3) ...
Selecting previously unselected package libjbig0:amd64.
Preparing to unpack .../libjbig0_2.1-3.1_amd64.deb ...
Unpacking libjbig0:amd64 (2.1-3.1) ...
Selecting previously unselected package fonts-dejavu-core.
Preparing to unpack .../fonts-dejavu-core_2.35-1_all.deb ...
Unpacking fonts-dejavu-core (2.35-1) ...
Selecting previously unselected package fontconfig-config.
Preparing to unpack .../fontconfig-config_2.11.94-0ubuntu1.1_all.deb ...
Unpacking fontconfig-config (2.11.94-0ubuntu1.1) ...
Selecting previously unselected package libfontconfig1:amd64.
Preparing to unpack .../libfontconfig1_2.11.94-0ubuntu1.1_amd64.deb ...
Unpacking libfontconfig1:amd64 (2.11.94-0ubuntu1.1) ...
Selecting previously unselected package libjpeg8:amd64.
Preparing to unpack .../libjpeg8_8c-2ubuntu8_amd64.deb ...
Unpacking libjpeg8:amd64 (8c-2ubuntu8) ...
Selecting previously unselected package libtiff5:amd64.
Preparing to unpack .../libtiff5_4.0.6-1ubuntu0.1_amd64.deb ...
Unpacking libtiff5:amd64 (4.0.6-1ubuntu0.1) ...
Selecting previously unselected package libvpx3:amd64.
Preparing to unpack .../libvpx3_1.5.0-2ubuntu1_amd64.deb ...
Unpacking libvpx3:amd64 (1.5.0-2ubuntu1) ...
Selecting previously unselected package libxpm4:amd64.
Preparing to unpack .../libxpm4_1%3a3.5.11-1ubuntu0.16.04.1_amd64.deb ...
Unpacking libxpm4:amd64 (1:3.5.11-1ubuntu0.16.04.1) ...
Selecting previously unselected package libgd3:amd64.
Preparing to unpack .../libgd3_2.1.1-4ubuntu0.16.04.6_amd64.deb ...
Unpacking libgd3:amd64 (2.1.1-4ubuntu0.16.04.6) ...
Selecting previously unselected package libxslt1.1:amd64.
Preparing to unpack .../libxslt1.1_1.1.28-2.1_amd64.deb ...
Unpacking libxslt1.1:amd64 (1.1.28-2.1) ...
Selecting previously unselected package nginx-common.
Preparing to unpack .../nginx-common_1.10.0-0ubuntu0.16.04.4_all.deb ...
Unpacking nginx-common (1.10.0-0ubuntu0.16.04.4) ...
Selecting previously unselected package nginx-core.
Preparing to unpack .../nginx-core_1.10.0-0ubuntu0.16.04.4_amd64.deb ...
Unpacking nginx-core (1.10.0-0ubuntu0.16.04.4) ...
Selecting previously unselected package nginx.
Preparing to unpack .../nginx_1.10.0-0ubuntu0.16.04.4_all.deb ...
Unpacking nginx (1.10.0-0ubuntu0.16.04.4) ...
Processing triggers for libc-bin (2.23-0ubuntu7) ...
Processing triggers for man-db (2.7.5-1) ...
Processing triggers for ufw (0.35-0ubuntu2) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for systemd (229-4ubuntu13) ...
Setting up libjpeg-turbo8:amd64 (1.4.2-0ubuntu3) ...
Setting up libjbig0:amd64 (2.1-3.1) ...
Setting up fonts-dejavu-core (2.35-1) ...
Setting up fontconfig-config (2.11.94-0ubuntu1.1) ...
Setting up libfontconfig1:amd64 (2.11.94-0ubuntu1.1) ...
Setting up libjpeg8:amd64 (8c-2ubuntu8) ...
Setting up libtiff5:amd64 (4.0.6-1ubuntu0.1) ...
Setting up libvpx3:amd64 (1.5.0-2ubuntu1) ...
Setting up libxpm4:amd64 (1:3.5.11-1ubuntu0.16.04.1) ...
Setting up libgd3:amd64 (2.1.1-4ubuntu0.16.04.6) ...
Setting up libxslt1.1:amd64 (1.1.28-2.1) ...
Setting up nginx-common (1.10.0-0ubuntu0.16.04.4) ...
Setting up nginx-core (1.10.0-0ubuntu0.16.04.4) ...
Setting up nginx (1.10.0-0ubuntu0.16.04.4) ...
Processing triggers for libc-bin (2.23-0ubuntu7) ...
Processing triggers for systemd (229-4ubuntu13) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for ufw (0.35-0ubuntu2) ...

After successful installation, start nginx service.

# service nginx start (Redhat systems)
Starting nginx:                                            [  OK  ]
OR
# systemctl start nginx (RHEL7 & debian)
Starting nginx:                                            [  OK  ]

Verify service is running.

# service nginx status
nginx (pid  1689) is running...

OR

# systemctl status nginx
● nginx.service - A high performance web server and a reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2017-04-04 10:24:19 UTC; 2min 15s ago
 Main PID: 6734 (nginx)
   CGroup: /system.slice/nginx.service
           ├─6734 nginx: master process /usr/sbin/nginx -g daemon on; master_process on
           └─6735 nginx: worker process

That’s it. Your installation is complete and your webserver is up and running.

Nginx server test

Now you can enter your server IP in the browser (http://x.x.x.x/) to check if your Nginx webserver is serving page or not. If you are getting a connection timed out, you may want to check firewall settings on your server to allow port 80.

You will be served with test page like below :

nginx test page on YUM based systems like Red Hat

nginx test page on APT based systems like Ubuntu

This confirms that your Nginx web server installation is successful and it’s ready for customization.

nginx configurations

The default server root directory is /usr/share/nginx/html. Files that are placed in there will be served on your web server. You can place your HTML files here to serve a static website! The test page you seen above is file index.html under /usr/share/nginx/html. This default directory can be changed under Nginx configuration file /etc/nginx/conf.d/default.conf.

nginx global configuration file is /etc/nginx/nginx.conf. In this conf file, you can set the user to run Nginx, its number of processes to fork, etc.

Default log files error.log (for errors) and access.log (logging accesses) are located under /var/log/nginx

Directory listing in nginx

If you place a few files or directories in root directory then you will not see a listing of them in your browser as we saw in Apache configuration. To enable this you need to add autoindex on; in config file after root directive. Look at my config below :

# cat /etc/nginx/conf.d/default.conf
server {
    listen       80 default_server;
    listen       [::]:80 default_server;
    server_name  _;
    root         /tmp;
    autoindex on;

----- output clipped ----

In the above config, I defined /tmp as root and turned on autoindex (highlighted lines). Restart Nginx services after saving the above changes. Now if I check my webpage (http://x.x.x.x/) it will list all files/directories under /tmp

You can see in above screenshot, /tmp directory listing is presented by Nginx. If you don’t put autoindex on then it will serve you 404 forbidden error!

Let’s Encrypt SSL certificate on Apache YUM based Linux system

Leave a reply

Learn to configure the free, open-source, secure Let’s Encrypt SSL certificate on Apache webserver running on YUM based Linux server.

What is Let’s Encrypt

Let’s Encrypt is free, open-source, and automatic SSL CA (Certificate Authority). Its managed by ISRG (Internet Security Research Group). SSL certificate always involved a cost which is recurring every year for renewal. Let’s encrypt aimed at open source and free SSL. This is an ideal choice for small websites, businesses which have less or no critical data on their websites and looking for SSL certificates.

If you are running a personal blog then SSL is essential for having a good search engine reputation. But before you dive into you need one dedicated IP for your domain name. If you are on shared hosting you are likely not having a dedicated IP. So for Let’s Encrypt SSL, you need to buy IP for your domain name.

Lets Encrypt SSL certificate

Let’s encrypt provides you fee SSL after your domain name validity which lasts for 3 months. You have to manually renew it every 3 months. The renewal process can be automatized too. Certbot is currently serving you deploying https on your server and configuring Let’s encrypt certs for you.

Before run into installation you should have these pre-requisite completed :

Install EPEL repo
You should have a webserver running
The webpage is being displayed on your domain name (port 80) properly

Let’s encrypt installation on Apache & YUM Linux system

First of all, you need to clone git repository of letsencrypt. For that install package ‘git’ first. Once done run below git clone command :

# git clone https://github.com/letsencrypt/letsencrypt
Initialized empty Git repository in /root/letsencrypt/.git/
remote: Counting objects: 45178, done.
remote: Compressing objects: 100% (164/164), done.
remote: Total 45178 (delta 112), reused 0 (delta 0), pack-reused 45014
Receiving objects: 100% (45178/45178), 13.38 MiB | 2.15 MiB/s, done.
Resolving deltas: 100% (32345/32345), done.

Now goto letsencrypt directory which is created in your present directory by clone command. Under that directory run below command :

# ./letsencrypt-auto  certonly --standalone

Saving debug log to /var/log/letsencrypt/letsencrypt.log
Please enter in your domain name(s) (comma and/or space separated)  (Enter 'c'
to cancel):ktwebtest.ddns.net
Obtaining a new certificate
Performing the following challenges:
tls-sni-01 challenge for ktwebtest.ddns.net
Waiting for verification...
Cleaning up challenges
Generating key (2048 bits): /etc/letsencrypt/keys/0002_key-certbot.pem
Creating CSR: /etc/letsencrypt/csr/0002_csr-certbot.pem

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at
   /etc/letsencrypt/live/ktwebtest.ddns.net/fullchain.pem. Your cert
   will expire on 2017-07-02. To obtain a new or tweaked version of
   this certificate in the future, simply run letsencrypt-auto again.
   To non-interactively renew *all* of your certificates, run
   "letsencrypt-auto renew"
 - If you like Certbot, please consider supporting our work by:

   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le

You can see above, after supplying domain name, Certbot creates a CSR file on its own, generates a key file, and fetch SSL certificate too. All paths are visible in the output. All files path are :

Key files directory: /etc/letsencrypt/keys/
CSR files directory: /etc/letsencrypt/csr/
SSL files directory: /etc/letsencrypt/live/

It also shows you when your certificate going to expire. And command you can use to renew your certificate. Now you can follow the tutorial of how to install SSL which you obtained in the above step.

You can even automatize this SSL installation steps by using command :

# ./letsencrypt-auto  -d ktwebtest.ddns.net --apache

With this command, it will create key, CSR, fetch SSL, install SSL on your domain webserver!

Certificate renewal

You can renew certificate manually using :

# ./letsencrypt-auto renew
Saving debug log to /var/log/letsencrypt/letsencrypt.log

-------------------------------------------------------------------------------
Processing /etc/letsencrypt/renewal/ktwebtest.ddns.net.conf
-------------------------------------------------------------------------------
Cert not yet due for renewal

The following certs are not due for renewal yet:
  /etc/letsencrypt/live/ktwebtest.ddns.net/fullchain.pem (skipped)
No renewals were attempted.

As you can see, it will scan through all fetched let’s encrypt certificates on the server and their due date. If found due, those certificates will be renewed in no time!

If you want to renew certificate regardless of the due date then you can use force renew as below :

# ./letsencrypt-auto renew  --force-renewal

Saving debug log to /var/log/letsencrypt/letsencrypt.log

-------------------------------------------------------------------------------
Processing /etc/letsencrypt/renewal/ktwebtest.ddns.net.conf
-------------------------------------------------------------------------------
Renewing an existing certificate
Performing the following challenges:
tls-sni-01 challenge for ktwebtest.ddns.net
Waiting for verification...
Cleaning up challenges
Generating key (2048 bits): /etc/letsencrypt/keys/0003_key-certbot.pem
Creating CSR: /etc/letsencrypt/csr/0003_csr-certbot.pem

-------------------------------------------------------------------------------
new certificate deployed without reload, fullchain is
/etc/letsencrypt/live/ktwebtest.ddns.net/fullchain.pem
-------------------------------------------------------------------------------

Congratulations, all renewals succeeded. The following certs have been renewed:
  /etc/letsencrypt/live/ktwebtest.ddns.net/fullchain.pem (success)

You can even schedule crontab with a little bit of scripting to have an automatic renewal of certificates.

How to install EPEL repository in YUM based Linux

Leave a reply

Learn how to install EPEL repository (Extra Packages for Enterprise Linux) in YUM based Linux. It enables you to install open source packages.

What is EPEL

EPEL stands for Extra Packages for Enterprise Linux. EPEL repository is helpful and rich with packages that are normally used/needed for commonly used Linux software. This repository is managed by the EPEL group. This repository contains all 100% free open source packages which may not available in the core

EPEL repos should be used in production with extra caution.

As you know EPEL group is the Fedora project, EPEL repository can be enabled for YUM based systems like RHEL, Oracle Linux, Fedora, CentOS, etc distributions.

How to configure EPEL

Adding EPEL repository can take a different route than adding https, FTP repositories in YUM. For EPFL, you need to download related RPM from link using any Linux downloaders. Choose correct distro and architecture while choosing a download link for the EPEL package. Or you can choose noarch rpm as I did below.

I downloaded rpm using wget as below :

# wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
--2017-04-03 13:18:35--  https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
Resolving dl.fedoraproject.org... 209.132.181.25, 209.132.181.23, 209.132.181.24
Connecting to dl.fedoraproject.org|209.132.181.25|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 14540 (14K) [application/x-rpm]
Saving to: “epel-release-latest-6.noarch.rpm”

100%[===================================================================================================================>] 14,540      51.5K/s   in 0.3s

2017-04-03 13:18:37 (51.5 KB/s) - “epel-release-latest-6.noarch.rpm” saved [14540/14540]

You should have rpm file in your current directory.

# ll
total 680
-rw-r--r--. 1 root root  14540 Nov  5  2012 epel-release-latest-6.noarch.rpm

You need to install rpm using yum command.

# yum install ./epel-release-latest-*.noarch.rpm
Loaded plugins: amazon-id, rhui-lb, security
Setting up Install Process
Examining ./epel-release-latest-6.noarch.rpm: epel-release-6-8.noarch
Marking ./epel-release-latest-6.noarch.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package epel-release.noarch 0:6-8 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

=============================================================================================================================================================
 Package                              Arch                           Version                     Repository                                             Size
=============================================================================================================================================================
Installing:
 epel-release                         noarch                         6-8                         /epel-release-latest-6.noarch                          22 k

Transaction Summary
=============================================================================================================================================================
Install       1 Package(s)

Total size: 22 k
Installed size: 22 k
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : epel-release-6-8.noarch                                                                                                                   1/1
  Verifying  : epel-release-6-8.noarch                                                                                                                   1/1

Installed:
  epel-release.noarch 0:6-8

Complete!

Thats it. EPEL repository is accommodated by your YUM configuration now.

EPEL repository test

Let’s test the EPEL repository if it’s configured properly. You should see below the new repo in directory /etc/yum.repos.d This is the first indication EPEL is configured.

# pwd
/etc/yum.repos.d

# ll
total 32
-rw-r--r--. 1 root root  957 Nov  4  2012 epel.repo
-rw-r--r--. 1 root root 1056 Nov  4  2012 epel-testing.repo

Now extract repolist from yum to verify configuration.

# yum repolist
Loaded plugins: amazon-id, rhui-lb, security
repo id                                                         repo name                                                                              status
epel                                                            Extra Packages for Enterprise Linux 6 - x86_64                                         12,361
rhui-REGION-client-config-server-6                              Red Hat Update Infrastructure 2.0 Client Configuration Server 6                             0
rhui-REGION-rhel-server-releases                                Red Hat Enterprise Linux Server 6 (RPMs)                                               19,422
rhui-REGION-rhel-server-releases-optional                       Red Hat Enterprise Linux Server 6 Optional (RPMs)                                      11,057
rhui-REGION-rhel-server-rh-common                               Red Hat Enterprise Linux Server 6 RH Common (RPMs)                                        129
repolist: 48,031

You can see EPEL is configured and identified properly by YUM (highlighted line).

How to install Apache webserver in Linux

Leave a reply

Step by step procedure to install and configure Apache webserver in Linux. It also includes troubleshooting steps for errors during install.

In this tutorial, we are going to see how to install and configure Apache webserver in Linux. Apache is the most widely used web server that is developed and maintained by Apache Software Foundation. Its an open-source software and available for free to download and use.

What is webserver

The webserver is aimed to serve web pages to its clients. In our daily life websites, we visit from browsers that are hosted on webservers! Webserver commonly runs on port 80 (HTTP protocol) and 443 (https protocol, more secured). Communication between the web server and its client over https protocol is encrypted and hence secured.

Apache webserver

Apache webserver is an open-source web server developed by Apache Software Foundation. It is named as Apache HTTP Server Project and details can be viewed here. Apache webserver is also a part of the LAMP stack. Read more about LAMP here. Let’s see how to set up the Apache web server on the Linux box.

Apache installation

If you have configured YUM repositories then you can install ‘httpd’ package. If you don’t have YUM or apt-get repositories configured you can download the latest Apache source, compile and then install it.

Number of errors and their solutions :

Error: configure: error: APR not found.
Solution: Install apr and apr-utils packages (download here if you don’t have yum)

Error: configure: error: no acceptable C compiler found in $PATH
Solution: Install GCC package

Error: configure: error: pcre-config for libpcre not found.
Solution: Install pcre package (download here, unzip, /configure --prefix=/usr/local/pcre, make, make install)

Finally, you should be able to install it using : ./configure --prefix=/apache, make, make install (you can change /apache directory to diff where it will be installed)

Apache configuration

Post-installation you will have /var/www/html/ directory in which you should place your HTML pages which can be fetched from browser. httpd service will come to existence.

If you keep files and directories in /var/www/html/ then its listing will be shown in a browser like this example we saw in another post. We will put below HTML file in /var/www/html/ for test :

# cat test.html
<html>
<body>
<h4>This webserver is installed by kerneltalks.com</h4>
</body>
</html>

Now once you make changes in the directory structure, restart httpd service. Verify httpd service is running and port 80 is listening.

# service httpd status
httpd (pid  27920) is running...

Now, try to fetch that page from browser. Use your server IP as website address i.e. http://IP/test.html

You will be greeted with such a page! Your webserver is up and running. Accepting and serving requests from browsers.

Apache config files

Apache configuration file located at /etc/httpd/conf/httpd.conf In this configuration file you can set your error file path, SSL certificate path, SSL cert key file path, port, IP (virtual hosts), access log path, etc. There is a lot more customization that can be done using this file but I stated only general tweaking parameters.

Apache log files can be found at :

/etc/httpd/logs/access_log: all access logs logged here.
/etc/httpd/logs/error_log: All errors logged here. They also include start-stop service messages.

How to start / stop Apache webserver

To start Apache webserver

# service httpd start
# service apache2 start   #If you are running Apache2

To stop Apache webserver

# service httpd stop
# service apache2 stop   #If you are running Apache2

How to load Apache2 modules

One of the common issues found is when the PHP module is not loaded into Apache webserver, .php links on webserver will download files in the browser instead of displaying them. To correct this you need to load the PHP module in Apache.

To load PHP or any other module in Apache, you need to add it in file /etc/sysconfig/apache2 in below line :

APACHE_MODULES="actions alias auth_basic authn_file authz_host authz_groupfile authz_core authz_user autoindex cgi dir env expires include log_config mime negotiation setenvif ssl socache_shmcb userdir reqtimeout authn_core php5"

Here you can see we are loading the php5 module in our Apache2 webserver. Then you need to restart Apache2 webserver. Once done, check if the PHP module is loaded or not. Use command apache2ctl -M to check loaded modules in Apache.

How to list Apache modules in Linux

 # apache2ctl -M
Loaded Modules:
 core_module (static)
 so_module (static)
 http_module (static)
 mpm_prefork_module (static)
 unixd_module (static)
 systemd_module (static)
 actions_module (shared)
 alias_module (shared)
 auth_basic_module (shared)
 authn_file_module (shared)
 authz_host_module (shared)
 authz_groupfile_module (shared)
 authz_core_module (shared)
 authz_user_module (shared)
 autoindex_module (shared)
 cgi_module (shared)
 dir_module (shared)
 env_module (shared)
 expires_module (shared)
 include_module (shared)
 log_config_module (shared)
 mime_module (shared)
 negotiation_module (shared)
 setenvif_module (shared)
 ssl_module (shared)
 socache_shmcb_module (shared)
 userdir_module (shared)
 reqtimeout_module (shared)
 authn_core_module (shared)
 php5_module (shared)

You can see our php5 module is loaded in Apache.

What is difference between Server Root and Document Root in Apache ?

Server root is where Apache executable binaries reside rather its an installation path for Apache. Whereas document root is where website pages reside i.e. from where webserver loads web pages. So, you can change Document Root if you don’t want to use default /srv/www/htdocs directory. You can change it to any directory where you keep your website pages.

List WWN of online FC in HPUX server

Leave a reply

List of commands to check WWN of online FC in the HPUX server. The article also includes a small script that can do this task in seconds!

For FC connectivity to storage on the HPUX server, we must share the WWN of the online FC. Getting WWN is a three-step process :

Step 1:

Identify FC devices under ioscan output.

# ioscan -fnCfc
Class     I  H/W Path    Driver S/W State   H/W Type     Description
==================================================================
fc        0  2/0/10/1/0  fcd   CLAIMED     INTERFACE    HP AB379-60101 4Gb Dual Port PCI/PCI-X Fibre Channel Adapter (FC Port 1)
                        /dev/fcd0
fc        1  2/0/10/1/1  fcd   CLAIMED     INTERFACE    HP AB379-60101 4Gb Dual Port PCI/PCI-X Fibre Channel Adapter (FC Port 2)
                        /dev/fcd1
fc        2  2/0/12/1/0  fcd   CLAIMED     INTERFACE    HP AB379-60101 4Gb Dual Port PCI/PCI-X Fibre Channel Adapter (FC Port 1)
                        /dev/fcd2
fc        3  2/0/12/1/1  fcd   CLAIMED     INTERFACE    HP AB379-60101 4Gb Dual Port PCI/PCI-X Fibre Channel Adapter (FC Port 2)
                        /dev/fcd3

In above output, you can see /dev/fcd0 to 3 are FC devices.

Step 2:

Check which FCs are online i.e. have cable connectivity with fcmsutil output.

# fcmsutil /dev/fcd0

                           Vendor ID is = 0x1077
                           Device ID is = 0x2422
            PCI Sub-system Vendor ID is = 0x103C
                   PCI Sub-system ID is = 0x12D7
                               PCI Mode = PCI-X 133 MHz
                       ISP Code version = 5.4.0
                       ISP Chip version = 3
                               Topology = PTTOPT_FABRIC
                             Link Speed = 4Gb
                     Local N_Port_id is = 0x010300
                  Previous N_Port_id is = None
            N_Port Node World Wide Name = 0x50060b00006975ed
            N_Port Port World Wide Name = 0x50060b00006975ec
            Switch Port World Wide Name = 0x200300051e046c0f
            Switch Node World Wide Name = 0x100000051e046c0f
              N_Port Symbolic Port Name = server1_fcd0
              N_Port Symbolic Node Name = server1_HP-UX_B.11.31
                           Driver state = ONLINE
                       Hardware Path is = 2/0/10/1/0
                     Maximum Frame Size = 2048
         Driver-Firmware Dump Available = NO
         Driver-Firmware Dump Timestamp = N/A
                                   TYPE = PFC
                         NPIV Supported = YES
                         Driver Version = @(#) fcd B.11.31.1103 Dec  6 2010

Check the driver state in the above output (highlighted). If it’s ONLINE that means this FC has cable connectivity. If its Awaiting Link UP then it does not have cable connectivity.

Step 3:

If it’s online check its WWN by checking N_Port Port World Wide Name value! That’s it. So WWN of above FC is 0x50060b00006975ec.

I have compiled all the above steps in a single script that you can run and get the WWN of online FC in seconds.

First test script in test server. Run it on your own risk.

Sample output :

# sh test.sh

FC : /dev/fcd0
0x50060b00006975ec

FC : /dev/fcd2
0x50060b00006973c8

pvcreate error: Device /dev/xyz not found (or ignored by filtering).

2 Replies

Solution for pvcreate error: Device /dev/xyz not found (or ignored by filtering). Troubleshooting steps and resolution for this error.

Sometimes when adding new disk/LUN to Linux machine using pvcreate you may come across below error :

Device /dev/xyz not found (or ignored by filtering).

# pvcreate /dev/sdb
  Device /dev/sdb not found (or ignored by filtering).

This is due to disk was used in different volume managers (possibly Linux own fdisk manager) and now you are trying to use it in LVM. To resolve this error, first, check if it has fdisk partitions using fdisk command :

# fdisk /dev/sdb

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): p

Disk /dev/sdb: 859.0 GB, 858993459200 bytes
255 heads, 63 sectors/track, 104433 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x62346fee6

    Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1      104433   838858041   83  Linux

In the above example, you can print the current partition table of the disk using p option under fdisk menu.

You can see there is one primary partition detected using fdisk. Because of this LVM command to initialize this disk (pvcreate) failed.

To resolve this you need to remove this partition and re-initialize disk in LVM. To delete partition use d option under fdisk menu.

# fdisk /dev/sdb

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help):d
Selected partition 1

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

After issuing delete d command under fdisk menu, you need to write (w) changes on disk. This will remove your existing partition on the disk. Once again you can use print p option to make sure that there is no fdisk partition on the disk.

You can now use disk in LVM without any issue.

# pvcreate /dev/sdb
  Physical volume "/dev/sdb" successfully created

If this solution doesn’t work for you or there were no partitions on disk previously and still, if you get this error then you may want to look at your multipath configurations. The hint is to look at your verbose pvcreate output to check where it’s failing. Use pvcreate -vvv /dev/<name> command.

YUM cheat sheet

Leave a reply

All YUM related articles in one place! Helpful YUM cheat sheet to learn, understand, revise YUM related sysadmin tasks on a single page.

YUM is Yellow dog Updater Modified. Its a package management tool for RPM-based systems. It has below a list of features that make it must use for every sysadmin.

Simple install, uninstall, upgrade operations for packages
Automatic resolves software dependency while installing or upgrading
Looks for more than one source for software (supports multiple repositories)
Supports CLI and GUI
Automatically detects architecture of the system and search for best-fit software version
Works well with remote (network connectivity) and local (without network connectivity) repositories.

In this article, I am gathering all YUM related posts in one place so that you don’t have to search them through our site!

Package Operations

Configurations

Services

Miscellaneous

How to check if package is installed

How to configure yum server in Linux

Leave a reply

Learn to configure the yum server in RPM-based Linux systems. The article explains yum server configs over HTTP and FTP protocol.

In our last article, we saw yum configurations. We learned what is yum, why to use it, what is repository, yum config file locations, config file format, how to configure DVD, HTTP locations as a repository. In this article, we will walk through YUM server configuration i.e. configuring serverA as a YUM server so that other clients can configure serverA as a repo location.

YUM server http configuration

First of all, we need to install a web server on the system so that the HTTP page can be served by the system. Install httpd package using yum. Post-installation you will have /var/www/html directory which is home of your webserver. Create packages directory within it which will hold all packages. Now we have /var/www/html/packages directory to hold packages of our YUM server.

Start httpd service and verify you are able to access http://ip-address/packages in the browser. It should look like below :

Now, we need to copy package files (.rpm) into this directory. You can manually copy them from your OS DVD or you can download using wget from online official package mirrors. Once you populate /var/www/html/packages directory with .rpm files they are available to download from the browser but YUM won’t be able to recognize them.

For YUM (on client side) to fetch packages from the above directory you need to create an index of these files (.xml). You can create it using below command –

# createrepo /var/www/html/packages/
Spawning worker 0 with 3 pkgs
Workers Finished
Gathering worker results
Saving Primary metadata
Saving file lists metadata
Saving other metadata
Generating sqlite DBs
Sqlite DBs complete

Here I kept only 3 RPMs in the directory so you can see it started with 0 of 3 pkg! After completion of the above command, you can observe directory repodata is created in packages directory. And it contains repo detail files along with xml file.

# ll /var/www/html/packages/repodata/
total 40
-rw-r--r--. 1 root root 10121 Mar 23 15:38 196f88dd1e6b0b74bbd8b3a689e77a8f632650da7fa77db06f212536a2e75096-primary.sqlite.bz2
-rw-r--r--. 1 root root  4275 Mar 23 15:38 1fc168d13253247ba15d45806c8f33bfced19bb1bf5eca54fb1d6758c831085f-filelists.sqlite.bz2
-rw-r--r--. 1 root root  2733 Mar 23 15:38 59d6b723590f73c4a65162c2f6f378bae422c72756f3dec60b1c4ef87f954f4c-filelists.xml.gz
-rw-r--r--. 1 root root  3874 Mar 23 15:38 656867c9894e31f39a1ecd3e14da8d1fbd68bbdf099e5a5f3ecbb581cf9129e5-other.sqlite.bz2
-rw-r--r--. 1 root root  2968 Mar 23 15:38 8d9cb58a2cf732deb12ce3796a5bc71b04e5c5c93247f4e2ab76bff843e7a747-primary.xml.gz
-rw-r--r--. 1 root root  2449 Mar 23 15:38 b30ec7d46fafe3d5e0b375f9c8bc0df7e9e4f69dc404fdec93777ddf9b145ef3-other.xml.gz
-rw-r--r--. 1 root root  2985 Mar 23 15:38 repomd.xml

Now your location http://ip-address/packages is ready to be identified by client YUM to fetch packages. The next thing is to configure another Linux machine (client) with this HTTP path as repo and try installing packages (which you kept in packages directory obv).

YUM server ftp configuration

In the FTP scenario, we are keeping packages accessible to other machines over FTP rather than HTTP protocol. You need to configure FTP and keep packages directory in the FTP share.

Go through createrepo step explained above for the FTP share directory. Once done you can configure the client with FTP address to fetch packages from the yum server. Repo location entry in the client repo configuration file will be –

baseurl=ftp://ip-address/ftp-share

YUM configuration in Linux

Leave a reply

Learn YUM configuration in Linux. Understand what is yum, features of yum, what is a repository, and how to configure it.

YUM is Yellow dog Updated Modified. It is developed to maintain an RPM-based system. RPM is the Redhat Package Manager. YUM is a package manager with below features –

Simple install, uninstall, upgrade operations
Automatic resolves software dependency
Looks for more than one source for software
Supports CLI and GUI
Automatically detects architecture of the system and search for best-fit software version
Works well with remote (network connectivity) and local (without network connectivity) repositories.

All these features made it the best package manager. In this article, we will walk through Yum configuration steps. You can also browse through below yum related posts :

YUM configuration basics

Yum configuration has repositories defined. Repositories are the places where package files .rpm are located and yum searches, downloads files from repositories for installations. Repositories can be the local mount point file://path, remote FTP location ftp://link, HTTP location link http://link or http://login:password@link, https link or remote NFS mount point.

Yum configuration file is /etc/yum.conf and repository configuration files are located under /etc/yum.repos.d/ directory. All repository configuration files must have .repo extension so than yum can identify them and read their configurations.

Typical repo configuration file entry looks like below :

[rhel-source-beta]
name=Red Hat Enterprise Linux $releasever Beta - $basearch - Source
baseurl=ftp://ftp.redhat.com/pub/redhat/linux/beta/$releasever/en/os/SRPMS/
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-beta,file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

here –

[rhrl-source-beta] is a unique repository id.
name is a human readable repository name
baseurl is the location from where packages should be scanned and fetched
enabled denotes if this repo is enabled or not i.e. yum should use it or not
gpgcheck enable/disable GPG signature check
gpgkey is the location of GPG key

Out of these first 4 entries are mandatory for every repo location. Let’s see how to create a repo from the DVD ISO file.

Remember one repo configuration file can have more than one location listed.

You can even configure internet proxy for yum in this configuration file.

YUM repo configuration for DVD ISO

RPM-based Linux installation DVD has RPM files in it which are used to install packages at the time of OS installation. We can use this package and build our repo so that yum can use those packages!

First, you have to mount ISO file on system. Let’s assume we have mounted it on /mnt/dvd. Now we have to create a yum repo file for it. Lets create file dvdiso.repo under /etc/yum.repos.d/ directory. It should look like :

[dvdiso]
name=RedHat DVD ISO
baseurl=file:///mnt/dvd
enabled=1
gpgcheck=1
gpgkey=file:///mnt/dvd/RPM-GPG-KEY-redhat-6

Male sure you check the path of GPG key on your ISO and edit accordingly. baseurl path will be a directory where repodata directory & gpg file lives.

Thats it! Your repo is ready. You can check using yum repolist command.

# yum repolist
Loaded plugins: refresh-packagekit, security
...
repo id                          repo name                                status
dvdiso                         RedHat DVD ISO                             25,459

In the above output, you can see repo is identified by yum. Now you can try installing any software from it with yum install command.

Make sure your ISO is always mounted on the system even after a reboot (add an entry in /etc/fstab to run this repo successfully.

YUM repo configuration for http repo

There are many official and unofficial repositories are hosted on the internet and can be accessed over HTTP protocol. These repositories are large and may contain more packages than your DVD has. To use them in yum, your server should have an active internet connection and it should be able to connect with HTTP locations you are trying to configure.

Once connectivity is confirmed create new repo file for them e.g. named weblocations.repo under directory /etc/yum.repos.d/ with content as below (for example) :

[centos]
name=CentOS Repository
baseurl=http://mirror.cisp.com/CentOS/6/os/i386/
enabled=1
gpgcheck=1
gpgkey=http://mirror.cisp.com/CentOS/6/os/i386/RPM-GPG-KEY-CentOS-6
[rhel-server-releases-optional]
name=Red Hat Enterprise Linux Server 6 Optional (RPMs) mirrorlist=https://redhat.com/pulp/mirror/content/dist/rhel/rhui/server/6/$releasever/$basearch/optional/os enabled=0 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release sslverify=1 sslclientkey=/etc/pki/rhui/content-rhel6.key sslclientcert=/etc/pki/rhui/product/content-rhel6.crt sslcacert=/etc/pki/rhui/cdn.redhat.com-chain.crt

In the above example, you can see 2 web locations are configured in the repo. First is HTTP for centOS whereas the second one is RHEL supplied with https mirror list. Since https protocol is used other SSL related config can be seen following it.

Time to check repo –

# yum repolist
Loaded plugins: rhui-lb, security
repo id                                                         repo name                                                                              status
centos                                                          CentOS Repository                                                                       5,062
rhui-REGION-rhel-server-releases-optional                       Red Hat Enterprise Linux Server 6 Optional (RPMs)                                      11,057

Both repo are identified by yum. Configuration is successful.

Read about yum server configuration for FTP, HTTP, and client-side yum configuration in our other articles.

YUM certificate error

If you have an issue with your Red Hat Network certificate you will see below error while executing yum commands.

The certificate /usr/share/rhn/ULN-CA-CERT is expired. Please ensure you have the correct certificate and your system time is correct.

You need to update rhn-client-tools package and it will update certificate details.

If rhn-client-tools package is not installed properly you may see below error while executing yum commands-

rhn-plugin: ERROR: can not find RHNS CA file: /usr/share/rhn/ULN-CA-CERT

In this case, you need to reinstall or update rhn-client-tools package. If you are not using RHN on your server you can even safely remove this package from the system and get your yum working.

lolcat: a tool to rainbow color Linux terminal

Leave a reply

Paint your command outputs with rainbow color! Use lolcat (Ruby gem) tool and add some spice to the black putty terminal!

Another article to have some fun on your Linux terminal. In the past, we have seen few articles about fun in Linux terminal –

In this article, we will cover lolcat command which colors your terminal texts in rainbow fashion! See below GIF to start with –

See how lolcat command colors output in rainbow color scheme!

lolcat is available at its Git Repository for download. Lets setup lolcat on your server.

How to install lolcat tool

lolcat is Ruby gem hence you need to install Ruby first. Install packages rubygems ruby-devel & ruby on your system using yum or apt-get. Once successfully install, download the latest version of lolcat from its Git repository using wget and any Linux downloader.

Once downloaded, unzip it

# unzip master.zip
Archive:  master.zip
dfc68649f6bdac255d5be052d2123f3fbe3f555c
   creating: lolcat-master/
 extracting: lolcat-master/.gitignore
  inflating: lolcat-master/Gemfile
  inflating: lolcat-master/LICENSE
  inflating: lolcat-master/README.md
 extracting: lolcat-master/Rakefile
   creating: lolcat-master/ass/
  inflating: lolcat-master/ass/screenshot.png
   creating: lolcat-master/bin/
  inflating: lolcat-master/bin/lolcat
   creating: lolcat-master/lib/
  inflating: lolcat-master/lib/lolcat.rb
   creating: lolcat-master/lib/lolcat/
  inflating: lolcat-master/lib/lolcat/cat.rb
  inflating: lolcat-master/lib/lolcat/lol.rb
 extracting: lolcat-master/lib/lolcat/version.rb
  inflating: lolcat-master/lolcat.gemspec

and install it using Ruby gems.

# cd lolcat-master/bin
# gem install lolcat
Successfully installed lolcat-42.24.0
Parsing documentation for lolcat-42.24.0
1 gem installed

This confirms your successful installation of lolcat!

lolcat command to rainbow color output!

Its time to see lolcat in action. You can pipe it with any output of your choice and it will color your command output in rainbow color (a few examples below)!

# ps -ef |lolcat
# date | lolcat

Want some more fun?

lolcat comes with few options which will make it more fun on the terminal. Run command with -d and duration and it will color your output in running mode.

You can even combine it with text banners like figlet or toilet and have fun!