Learn how to create login banners in Linux to display a different warning or information message to the user who is about to log in or after he logs in.
Login banner messages in Linux
Whenever you log in to some production systems of the firm, you get to see some login messages, warnings, or info about the server you are about to log in or already logged in like below. Those are the login banners.
Login welcome messages in Linux
In this article we will walk you through how to configure them.
There are two types of banners you can configure.
Banner message to display before user logs in (configure in the file of your choice eg. /etc/login.warn)
Banner message to display after the user successfully logged in (configure in /etc/motd)
How to display message when user connects to system before login
This message will be displayed to the user when he connects to the server and before he logged in. This means when he enter the username, this message will be displayed before the password prompt.
You can use any filename and enter your message within. Here we used /etc/login.warn file and put our messages inside.
# cat /etc/login.warn
!!!! Welcome to KernelTalks test server !!!!
This server is meant for testing Linux commands and tools. If you are
not associated with kerneltalks.com and not authorized please dis-connect
immediately.
Now, you need to supply this file and path to sshd daemon so that it can fetch this banner for each user login request. For that open /etc/sshd/sshd_config file and search for the line #Banner none
Here you have to edit the file and write your filename and remove the hash mark. It should look like : Banner /etc/login.warn
Save the file and restart sshd daemon. To avoid disconnecting existing connected users, use the HUP signal to restart sshd.
That’s it! Open new sessions and try login. You will be greeted with the message you configured in the above steps.
Login banner in Linux
You can see the message is displayed before the user enters his password and log in to the system.
How to display message after user logs in
Message user sees after he logs into the system successfully is Message Of The Day & is controlled by /etc/motd file. Edit this file and enter the message you want to greet the user with once he successfully logged in.
root@kerneltalks # cat /etc/motd
W E L C O M E
Welcome to the testing environment of kerneltalks.
Feel free to use this system for testing your Linux
skills. In case of any issues reach out to admin at
info@kerneltalks.com. Thank you.
You don’t need to restart sshd daemon to take this change effect. As soon as you save the file, its content will be read and displayed by sshd daemon from the very next login request it serves.
Message Of The Day
You can see in the above screenshot: Yellow box is MOTD controlled by /etc/motd and the green box is what we saw earlier login banner.
You can use tools like cowsay, banner, figlet, lolcat to create fancy, eye-catching messages to display at login. This method works on almost all Linux distros like RedHat, Centos, Ubuntu, Fedora, etc.
Understand sosreport in detail. Learn how to generate sosreport and how to read sosreport in this article.
sosreport
sosreport is not a new term for RedHat lovers! Its a tool on RedHat Linux which helps you grab system information in a single tarball which can be shared with the vendor for troubleshooting issues.
Whenever you log a case with RedHat for RHEL, the first thing first they ask is for sosreport. In this article, we will see how to generate a sosreport and how to read sosreport.
If sosreport package is not installed on your system you will see below error –
root@kerneltalks # sosreport
-bash: sosreport: command not found
Install sos package using yum. You can follow the installation steps explained here. Below are the installation logs for your reference.
root@kerneltalks # yum install sos
Loaded plugins: amazon-id, rhui-lb, search-disabled-repos
Resolving Dependencies
--> Running transaction check
---> Package sos.noarch 0:3.4-6.el7 will be installed
--> Processing Dependency: bzip2 for package: sos-3.4-6.el7.noarch
--> Running transaction check
---> Package bzip2.x86_64 0:1.0.6-13.el7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
========================================================================================================================================================================
Package Arch Version Repository Size
========================================================================================================================================================================
Installing:
sos noarch 3.4-6.el7 rhui-REGION-rhel-server-releases 381 k
Installing for dependencies:
bzip2 x86_64 1.0.6-13.el7 rhui-REGION-rhel-server-releases 52 k
Transaction Summary
========================================================================================================================================================================
Install 1 Package (+1 Dependent package)
Total download size: 433 k
Installed size: 1.4 M
Is this ok [y/d/N]: y
Downloading packages:
(1/2): sos-3.4-6.el7.noarch.rpm | 381 kB 00:00:00
(2/2): bzip2-1.0.6-13.el7.x86_64.rpm | 52 kB 00:00:00
------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 610 kB/s | 433 kB 00:00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : bzip2-1.0.6-13.el7.x86_64 1/2
Installing : sos-3.4-6.el7.noarch 2/2
Verifying : sos-3.4-6.el7.noarch 1/2
Verifying : bzip2-1.0.6-13.el7.x86_64 2/2
Installed:
sos.noarch 0:3.4-6.el7
Dependency Installed:
bzip2.x86_64 0:1.0.6-13.el7
Complete!
How to generate sosreport
To generate a sosreport you just need to run sosreport command. It saves the report in /var/tmp by default so make sure you have enough breathing space in /var mount point.
Output file follows naming conventions as sosreport-name.caseID-yyyymmddhhmmss.tar.xz where –
name is Name you provide or hostname by default
caseID if you provide or blank
Date in yyyymmdd format
Time in hhmmss
Its a tarball with compression. After running the command it will ask you name and case ID and then start executing its modules which collects all system information and save it into a tarball.
root@kerneltalks # sosreport
sosreport (version 3.4)
This command will collect diagnostic and configuration information from
this Red Hat Enterprise Linux system and installed applications.
An archive containing the collected information will be generated in
/var/tmp/sos.iNadXY and may be provided to a Red Hat support
representative.
Any information provided to Red Hat will be treated in accordance with
the published support policies at:
https://access.redhat.com/support/
The generated archive may contain data considered sensitive and its
content should be reviewed by the originating organization before being
passed to any third party.
No changes will be made to system configuration.
Press ENTER to continue, or CTRL-C to quit.
Please enter your first initial and last name [kerneltalks]: Shrikant Lavhate
Please enter the case id that you are generating this report for []: 12345678
Setting up archive ...
Setting up plugins ...
Running plugins. Please wait ...
Running 74/74: yum... er...
Creating compressed archive...
Your sosreport has been generated and saved in:
/var/tmp/sosreport-ShrikantLavhate.12345678-20171105171210.tar.xz
The checksum is: 502b698f6052964ca1c2d348ea7e67a4
Please send this file to your support representative.
Command also shows you checksum of the output file. This will be helpful in checking the integrity of the file when it reaches destination party like vendor etc.
The output report generated above is the tarball file. You can un-tar it and read it on your own as well.
root@kerneltalks # tar xvf /var/tmp/sosreport-ShrikantLavhate.12345678-20171105171210.tar.xz
After extracting tarball you can see directory created with tarball name. Under which you can file many files and directories.
root@kerneltalks # ls -lrt sosreport-ShrikantLavhate.12345678-20171105171210
total 16
drwxr-xr-x. 5 root root 42 Jul 11 15:57 usr
dr-xr-xr-x. 3 root root 19 Jul 11 16:07 boot
dr-xr-xr-x. 10 root root 4096 Nov 5 12:19 proc
dr-xr-xr-x. 10 root root 112 Nov 5 12:19 sys
drwxr-xr-x. 4 root root 28 Nov 5 12:19 var
drwxr-xr-x. 2 root root 18 Nov 5 12:19 dev
dr-xr-xr-x. 7 root root 78 Nov 5 12:24 lib
dr-xr-x---. 2 root root 29 Nov 5 16:23 root
drwxr-xr-x. 34 root root 4096 Nov 5 17:08 etc
lrwxrwxrwx. 1 root root 29 Nov 5 17:12 mount -> sos_commands/filesys/mount_-l
lrwxrwxrwx. 1 root root 27 Nov 5 17:12 df -> sos_commands/filesys/df_-al
lrwxrwxrwx. 1 root root 27 Nov 5 17:12 uptime -> sos_commands/general/uptime
lrwxrwxrwx. 1 root root 28 Nov 5 17:12 uname -> sos_commands/kernel/uname_-a
drwx------. 3 root root 18 Nov 5 17:12 sos_strings
lrwxrwxrwx. 1 root root 25 Nov 5 17:12 lsmod -> sos_commands/kernel/lsmod
lrwxrwxrwx. 1 root root 45 Nov 5 17:12 java -> sos_commands/java/alternatives_--display_java
lrwxrwxrwx. 1 root root 29 Nov 5 17:12 hostname -> sos_commands/general/hostname
lrwxrwxrwx. 1 root root 31 Nov 5 17:12 dmidecode -> sos_commands/hardware/dmidecode
lrwxrwxrwx. 1 root root 25 Nov 5 17:12 date -> sos_commands/general/date
lrwxrwxrwx. 1 root root 32 Nov 5 17:12 route -> sos_commands/networking/route_-n
lrwxrwxrwx. 1 root root 30 Nov 5 17:12 ps -> sos_commands/process/ps_auxwww
lrwxrwxrwx. 1 root root 41 Nov 5 17:12 netstat -> sos_commands/networking/netstat_-W_-neopa
lrwxrwxrwx. 1 root root 22 Nov 5 17:12 last -> sos_commands/last/last
lrwxrwxrwx. 1 root root 34 Nov 5 17:12 ip_addr -> sos_commands/networking/ip_-o_addr
lrwxrwxrwx. 1 root root 24 Nov 5 17:12 free -> sos_commands/memory/free
lrwxrwxrwx. 1 root root 130 Nov 5 17:12 installed-rpms -> sos_commands/rpm/sh_-c_rpm_--nodigest_-qa_--qf_NAME_-_VERSION_-_RELEASE_._ARCH_INSTALLTIME_date_awk_-F_printf_-59s_s_n_1_2_sort_-f
lrwxrwxrwx. 1 root root 38 Nov 5 17:12 chkconfig -> sos_commands/services/chkconfig_--list
-rw-r--r--. 1 root root 1481 Nov 5 17:12 version.txt
drwx------. 2 root root 37 Nov 5 17:12 sos_reports
drwx------. 2 root root 35 Nov 5 17:12 sos_logs
drwx------. 43 root root 4096 Nov 5 17:12 sos_commands
drwxr-xr-x. 3 root root 19 Nov 5 17:12 run
Navigate to sos_reports directory within which you will find sos.txt & sos.html file.
In sos.txt file you can see all the plugins loaded, the command executed, files copied by sosreport. In sos.html file, all these things are hyperlinked to their original content within the directory. So you can directly view command output or files which are copied by script.
If there are any alerts detected by sosreport it will highlight those at the very beginning of these files.
This information is for sosreport version 3.4. If you are running different version there might be small differences in information.
I mounted it on the NFS client client1 successfully. I am able to read all data within this directory from the NFS client.
root@client1 # mount kerneltalks:/mydata /nfs_data
root@client1 # ls -lrt /nfs_data
Issue
I am not able to create a file or directory in the NFS mount even if rw option is set. I tried creating files, directory and I get access denied error.
By default, NFS prevents remote root users from gaining root-level privileges on its exports. It assigns user privileges of nfsnobody user to remotely logged in root users. This is what happened here and hence even if rw option is set, since we are using mount at root user we are not able to write any data on export.
This is called squashing root privileges to the normal ones. This to ensure accidental writing or modifying data on exports. You can set all_squash option which will squash privileges of all remote users including root to normal user nfsnobody.
For our issue, we have to set no_root_squash option on export so that remote root user keeps his power intact and will be able to write on the exported directory.
I re-exported directory using exportfs. Re-exporting mount points does not require the client to un-mount exported directories. Re-export also avoid the NFS server restart and catch up with new configuration.
root@kerneltalks # exportfs -ra
That’s it! Now I am able to create files and directories in the exported directory on NFS client.
When you are using NFS mount points with root account on client-side then export them with no_root_squash option. This will ensure you don’t face access related issues on NFS mount points.
Learn the search power tool Googler to search keywords on Google from the Linux terminal. The text-based search tool works on all Linux distros.
Googler! Logo @github.com/jarun/googler
One of the most visited sites by IT people is Google! Sample code, syntax, errors, solutions, tutorials, howtos we search all these things on Google every day. No one knows everything! No one can deny that he/she never used Google! So it’s an inseparable part of digital life.
What if you could Google right from your Linux terminal! Sounds crazy! Obviously Googling in text mode won’t be that easy-to-use experience but yes for Linux lovers its fascinating and must-do experience.
In this article, we will walk you through how to Google in Linux terminal.
Googler is a tool that provides the capability to search on Google from the Linux terminal. We will see how to install Googler and how to use Googler to search from the Linux terminal.
About Googler
Googler is a command-line utility originally started by Henri Hakkinen and now taken forward by Arun Jana. Its GIT repo is maintained here. When searched, it shows results with title, link, and excerpt in terminal window.
Take a look of Googler in action :
Googler searching kerneltalks on Google
How to install Googler
The Googler uses Python and the latest release needs Python 3 or later to run. Install Python 3 on your system if you don’t have it.
After a successful package installation, you will be able to run googler command. If you want to compile it on your system using source code then source code is available here.
How to use Googler
Googler has many options to search and interact with results. For simple search you just supply keyword and it will show you the first 10 search results the same as Google website do when you search keyword from browser.
Output is color coded for easy reading and identification where –
Green for titles
Yellow for links
cyan for indices and link metadata like published date etc.
Normal for link description
See above screenshot where you can see simple keyword search in googler and the color scheme.
If you run googler command without any argument it asks for a keyword or offers help via ?
root@kerneltalks # googler
Please initiate a query.
googler (? for help) ?
omniprompt keys:
n, p fetch the next or previous set of search results
index open the result corresponding to index in browser
f jump to the first page
o [index|range|a ...] open space-separated result indices, numeric ranges
(sitelinks unsupported in ranges), or all, in browser
open the current search in browser, if no arguments
O [index|range|a ...] like key 'o', but try to open in a GUI browser
g keywords new Google search for 'keywords' with original options
should be used to search omniprompt keys and indices
q, ^D, double Enter exit googler
? show omniprompt help
* other inputs issue a new search with original options
Here are few searches you can try with Googler :
Search within news for keyword
# googler -N Linux
Search on specific website
# googler -w kerneltalks.com nfs
Search specific filetype
# googler linux tutorial filetype:pdf
Many options to explore and use. Check googler manpage using man googler or help using googler -h !!
Learn how to install python 3 on Linux like Redhat, centos, ubuntu, etc. Also, learn how to get rid of a few python related errors.
Python 3 installation steps
By default, all of the Linux distros have pre-installed Python. Most of it is Python 2.x. not Python 3.x. Many of nowadays tools, scripts, etc need Python version 3 (python3) for compiling.
In this article, we will see how to install python3 step by step on Linux like RHEL, centos, ubuntu, etc.
If your package manager repo does offer python3 for install then you can easily install it from there,. If not then follow this process to install from source code.
Let’s get into the step by step Python installation from its source code. As of today, the Latest Python release is 3.6.3 and it’s available here.
Step 1.
Download source code from the Python website on your server using tools like wget. We are using the latest release link here.
root@kerneltalks # tar xf Python-3.6.3.tar.xz
root@kerneltalks # cd Python-3.6.3
Step 3.
Now its time to compile the source code. Execute configure script in Python-3.6.3 directory.
root@kerneltalks # ./configure
checking build system type... x86_64-pc-linux-gnu
checking host system type... x86_64-pc-linux-gnu
checking for python3.6... no
checking for python3... no
checking for python... python
checking for --enable-universalsdk... no
checking for --with-universal-archs... no
checking MACHDEP... linux
checking for --without-gcc... no
checking for --with-icc... no
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking how to run the C preprocessor... gcc -E
checking for grep that handles long lines and -e... /bin/grep
checking for a sed that does not truncate output... /bin/sed
checking for --with-cxx-main=<compiler>... no
checking for g++... no
configure:
By default, distutils will build C++ extension modules with "g++".
If this is not intended, then set CXX on the configure command line.
checking for the platform triplet based on compiler characteristics... x86_64-linux-gnu
checking for -Wl,--no-as-needed... yes
checking for egrep... /bin/grep -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking minix/config.h usability... no
checking minix/config.h presence... no
checking for minix/config.h... no
checking whether it is safe to define __EXTENSIONS__... yes
checking for the Android API level... not Android
checking for --with-suffix...
checking for case-insensitive build directory... no
checking LIBRARY... libpython$(VERSION)$(ABIFLAGS).a
checking LINKCC... $(PURIFY) $(MAINCC)
checking for GNU ld... yes
checking for inline... inline
checking for --enable-shared... no
checking for --enable-profiling... no
checking LDLIBRARY... libpython$(VERSION)$(ABIFLAGS).a
checking for ranlib... ranlib
checking for ar... ar
checking for readelf... readelf
checking for a BSD-compatible install... /bin/install -c
checking for a thread-safe mkdir -p... /bin/mkdir -p
checking for --with-pydebug... no
checking for --with-assertions... no
checking for --enable-optimizations... no
checking for --with-lto... no
checking target system type... x86_64-pc-linux-gnu
checking for -llvm-profdata... no
checking for llvm-profdata... ''
checking for -Wextra... yes
checking whether gcc accepts and needs -fno-strict-aliasing... no
checking if we can turn off gcc unused result warning... yes
checking if we can turn off gcc unused parameter warning... yes
checking if we can turn off gcc missing field initializers warning... yes
checking if we can turn on gcc mixed sign comparison warning... yes
checking if we can turn on gcc unreachable code warning... no
checking whether pthreads are available without options... no
checking whether gcc accepts -Kpthread... no
checking whether gcc accepts -Kthread... no
checking whether gcc accepts -pthread... yes
checking whether g++ also accepts flags for thread support... no
checking for ANSI C header files... (cached) yes
checking asm/types.h usability... yes
checking asm/types.h presence... yes
checking for asm/types.h... yes
checking conio.h usability... no
checking conio.h presence... no
checking for conio.h... no
checking direct.h usability... no
checking direct.h presence... no
checking for direct.h... no
checking dlfcn.h usability... yes
checking dlfcn.h presence... yes
checking for dlfcn.h... yes
checking errno.h usability... yes
checking errno.h presence... yes
checking for errno.h... yes
checking fcntl.h usability... yes
checking fcntl.h presence... yes
checking for fcntl.h... yes
checking grp.h usability... yes
checking grp.h presence... yes
checking for grp.h... yes
checking ieeefp.h usability... no
checking ieeefp.h presence... no
checking for ieeefp.h... no
checking io.h usability... no
checking io.h presence... no
checking for io.h... no
checking langinfo.h usability... yes
checking langinfo.h presence... yes
checking for langinfo.h... yes
checking libintl.h usability... yes
checking libintl.h presence... yes
checking for libintl.h... yes
checking process.h usability... no
checking process.h presence... no
checking for process.h... no
checking pthread.h usability... yes
checking pthread.h presence... yes
checking for pthread.h... yes
checking sched.h usability... yes
checking sched.h presence... yes
checking for sched.h... yes
checking shadow.h usability... yes
checking shadow.h presence... yes
checking for shadow.h... yes
checking signal.h usability... yes
checking signal.h presence... yes
checking for signal.h... yes
checking stropts.h usability... no
checking stropts.h presence... no
checking for stropts.h... no
checking termios.h usability... yes
checking termios.h presence... yes
checking for termios.h... yes
checking for unistd.h... (cached) yes
checking utime.h usability... yes
checking utime.h presence... yes
checking for utime.h... yes
checking poll.h usability... yes
checking poll.h presence... yes
checking for poll.h... yes
checking sys/devpoll.h usability... no
checking sys/devpoll.h presence... no
checking for sys/devpoll.h... no
checking sys/epoll.h usability... yes
checking sys/epoll.h presence... yes
checking for sys/epoll.h... yes
checking sys/poll.h usability... yes
checking sys/poll.h presence... yes
checking for sys/poll.h... yes
checking sys/audioio.h usability... no
checking sys/audioio.h presence... no
checking for sys/audioio.h... no
checking sys/xattr.h usability... yes
checking sys/xattr.h presence... yes
checking for sys/xattr.h... yes
checking sys/bsdtty.h usability... no
checking sys/bsdtty.h presence... no
checking for sys/bsdtty.h... no
checking sys/event.h usability... no
checking sys/event.h presence... no
checking for sys/event.h... no
checking sys/file.h usability... yes
checking sys/file.h presence... yes
checking for sys/file.h... yes
checking sys/ioctl.h usability... yes
checking sys/ioctl.h presence... yes
checking for sys/ioctl.h... yes
checking sys/kern_control.h usability... no
checking sys/kern_control.h presence... no
checking for sys/kern_control.h... no
checking sys/loadavg.h usability... no
checking sys/loadavg.h presence... no
checking for sys/loadavg.h... no
checking sys/lock.h usability... no
checking sys/lock.h presence... no
checking for sys/lock.h... no
checking sys/mkdev.h usability... no
checking sys/mkdev.h presence... no
checking for sys/mkdev.h... no
checking sys/modem.h usability... no
checking sys/modem.h presence... no
checking for sys/modem.h... no
checking sys/param.h usability... yes
checking sys/param.h presence... yes
checking for sys/param.h... yes
checking sys/random.h usability... no
checking sys/random.h presence... no
checking for sys/random.h... no
checking sys/select.h usability... yes
checking sys/select.h presence... yes
checking for sys/select.h... yes
checking sys/sendfile.h usability... yes
checking sys/sendfile.h presence... yes
checking for sys/sendfile.h... yes
checking sys/socket.h usability... yes
checking sys/socket.h presence... yes
checking for sys/socket.h... yes
checking sys/statvfs.h usability... yes
checking sys/statvfs.h presence... yes
checking for sys/statvfs.h... yes
checking for sys/stat.h... (cached) yes
checking sys/syscall.h usability... yes
checking sys/syscall.h presence... yes
checking for sys/syscall.h... yes
checking sys/sys_domain.h usability... no
checking sys/sys_domain.h presence... no
checking for sys/sys_domain.h... no
checking sys/termio.h usability... no
checking sys/termio.h presence... no
checking for sys/termio.h... no
checking sys/time.h usability... yes
checking sys/time.h presence... yes
checking for sys/time.h... yes
checking sys/times.h usability... yes
checking sys/times.h presence... yes
checking for sys/times.h... yes
checking for sys/types.h... (cached) yes
checking sys/uio.h usability... yes
checking sys/uio.h presence... yes
checking for sys/uio.h... yes
checking sys/un.h usability... yes
checking sys/un.h presence... yes
checking for sys/un.h... yes
checking sys/utsname.h usability... yes
checking sys/utsname.h presence... yes
checking for sys/utsname.h... yes
checking sys/wait.h usability... yes
checking sys/wait.h presence... yes
checking for sys/wait.h... yes
checking pty.h usability... yes
checking pty.h presence... yes
checking for pty.h... yes
checking libutil.h usability... no
checking libutil.h presence... no
checking for libutil.h... no
checking sys/resource.h usability... yes
checking sys/resource.h presence... yes
checking for sys/resource.h... yes
checking netpacket/packet.h usability... yes
checking netpacket/packet.h presence... yes
checking for netpacket/packet.h... yes
checking sysexits.h usability... yes
checking sysexits.h presence... yes
checking for sysexits.h... yes
checking bluetooth.h usability... no
checking bluetooth.h presence... no
checking for bluetooth.h... no
checking linux/tipc.h usability... yes
checking linux/tipc.h presence... yes
checking for linux/tipc.h... yes
checking linux/random.h usability... yes
checking linux/random.h presence... yes
checking for linux/random.h... yes
checking spawn.h usability... yes
checking spawn.h presence... yes
checking for spawn.h... yes
checking util.h usability... no
checking util.h presence... no
checking for util.h... no
checking alloca.h usability... yes
checking alloca.h presence... yes
checking for alloca.h... yes
checking endian.h usability... yes
checking endian.h presence... yes
checking for endian.h... yes
checking sys/endian.h usability... no
checking sys/endian.h presence... no
checking for sys/endian.h... no
checking sys/sysmacros.h usability... yes
checking sys/sysmacros.h presence... yes
checking for sys/sysmacros.h... yes
checking for dirent.h that defines DIR... yes
checking for library containing opendir... none required
checking whether sys/types.h defines makedev... yes
checking bluetooth/bluetooth.h usability... no
checking bluetooth/bluetooth.h presence... no
checking for bluetooth/bluetooth.h... no
checking for net/if.h... yes
checking for linux/netlink.h... yes
checking for linux/can.h... yes
checking for linux/can/raw.h... yes
checking for linux/can/bcm.h... yes
checking for clock_t in time.h... yes
checking for makedev... yes
checking for le64toh... yes
checking Solaris LFS bug... no
checking for mode_t... yes
checking for off_t... yes
checking for pid_t... yes
checking for size_t... yes
checking for uid_t in sys/types.h... yes
checking for ssize_t... yes
checking for __uint128_t... yes
checking size of int... 4
checking size of long... 8
checking size of long long... 8
checking size of void *... 8
checking size of short... 2
checking size of float... 4
checking size of double... 8
checking size of fpos_t... 16
checking size of size_t... 8
checking size of pid_t... 4
checking size of uintptr_t... 8
checking for long double support... yes
checking size of long double... 16
checking size of _Bool... 1
checking size of off_t... 8
checking whether to enable large file support... no
checking size of time_t... 8
checking for pthread_t... yes
checking size of pthread_t... 8
checking for --enable-framework... no
checking for dyld... no
checking the extension of shared libraries... .so
checking LDSHARED... $(CC) -shared
checking CCSHARED... -fPIC
checking LINKFORSHARED... -Xlinker -export-dynamic
checking CFLAGSFORSHARED...
checking SHLIBS... $(LIBS)
checking for sendfile in -lsendfile... no
checking for dlopen in -ldl... yes
checking for shl_load in -ldld... no
checking for library containing sem_init... -lpthread
checking for textdomain in -lintl... no
checking aligned memory access is required... no
checking for --with-hash-algorithm... default
checking for --with-address-sanitizer... no
checking for t_open in -lnsl... no
checking for socket in -lsocket... no
checking for --with-libs... no
checking for pkg-config... /bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for --with-system-expat... no
checking for --with-system-ffi... yes
checking for --with-system-libmpdec... no
checking for --enable-loadable-sqlite-extensions... no
checking for --with-tcltk-includes... default
checking for --with-tcltk-libs... default
checking for --with-dbmliborder...
checking for --with-threads... yes
checking if PTHREAD_SCOPE_SYSTEM is supported... yes
checking for pthread_sigmask... yes
checking for pthread_atfork... yes
checking if --enable-ipv6 is specified... yes
checking if RFC2553 API is available... yes
checking ipv6 stack type... linux-glibc
checking for CAN_RAW_FD_FRAMES... yes
checking for --with-doc-strings... yes
checking for --with-pymalloc... yes
checking for --with-valgrind... no
checking for --with-dtrace... no
checking for dlopen... yes
checking DYNLOADFILE... dynload_shlib.o
checking MACHDEP_OBJS... none
checking for alarm... yes
checking for accept4... yes
checking for setitimer... yes
checking for getitimer... yes
checking for bind_textdomain_codeset... yes
checking for chown... yes
checking for clock... yes
checking for confstr... yes
checking for ctermid... yes
checking for dup3... yes
checking for execv... yes
checking for faccessat... yes
checking for fchmod... yes
checking for fchmodat... yes
checking for fchown... yes
checking for fchownat... yes
checking for fexecve... yes
checking for fdopendir... yes
checking for fork... yes
checking for fpathconf... yes
checking for fstatat... yes
checking for ftime... yes
checking for ftruncate... yes
checking for futimesat... yes
checking for futimens... yes
checking for futimes... yes
checking for gai_strerror... yes
checking for getentropy... no
checking for getgrouplist... yes
checking for getgroups... yes
checking for getlogin... yes
checking for getloadavg... yes
checking for getpeername... yes
checking for getpgid... yes
checking for getpid... yes
checking for getpriority... yes
checking for getresuid... yes
checking for getresgid... yes
checking for getpwent... yes
checking for getspnam... yes
checking for getspent... yes
checking for getsid... yes
checking for getwd... yes
checking for initgroups... yes
checking for kill... yes
checking for killpg... yes
checking for lchmod... no
checking for lchown... yes
checking for linkat... yes
checking for lstat... yes
checking for lutimes... yes
checking for mmap... yes
checking for memrchr... yes
checking for mbrtowc... yes
checking for mkdirat... yes
checking for mkfifo... yes
checking for mkfifoat... yes
checking for mknod... yes
checking for mknodat... yes
checking for mktime... yes
checking for mremap... yes
checking for nice... yes
checking for openat... yes
checking for pathconf... yes
checking for pause... yes
checking for pipe2... yes
checking for plock... no
checking for poll... yes
checking for posix_fallocate... yes
checking for posix_fadvise... yes
checking for pread... yes
checking for pthread_init... no
checking for pthread_kill... yes
checking for putenv... yes
checking for pwrite... yes
checking for readlink... yes
checking for readlinkat... yes
checking for readv... yes
checking for realpath... yes
checking for renameat... yes
checking for select... yes
checking for sem_open... yes
checking for sem_timedwait... yes
checking for sem_getvalue... yes
checking for sem_unlink... yes
checking for sendfile... yes
checking for setegid... yes
checking for seteuid... yes
checking for setgid... yes
checking for sethostname... yes
checking for setlocale... yes
checking for setregid... yes
checking for setreuid... yes
checking for setresuid... yes
checking for setresgid... yes
checking for setsid... yes
checking for setpgid... yes
checking for setpgrp... yes
checking for setpriority... yes
checking for setuid... yes
checking for setvbuf... yes
checking for sched_get_priority_max... yes
checking for sched_setaffinity... yes
checking for sched_setscheduler... yes
checking for sched_setparam... yes
checking for sched_rr_get_interval... yes
checking for sigaction... yes
checking for sigaltstack... yes
checking for siginterrupt... yes
checking for sigpending... yes
checking for sigrelse... yes
checking for sigtimedwait... yes
checking for sigwait... yes
checking for sigwaitinfo... yes
checking for snprintf... yes
checking for strftime... yes
checking for strlcpy... no
checking for symlinkat... yes
checking for sync... yes
checking for sysconf... yes
checking for tcgetpgrp... yes
checking for tcsetpgrp... yes
checking for tempnam... yes
checking for timegm... yes
checking for times... yes
checking for tmpfile... yes
checking for tmpnam... yes
checking for tmpnam_r... yes
checking for truncate... yes
checking for uname... yes
checking for unlinkat... yes
checking for unsetenv... yes
checking for utimensat... yes
checking for utimes... yes
checking for waitid... yes
checking for waitpid... yes
checking for wait3... yes
checking for wait4... yes
checking for wcscoll... yes
checking for wcsftime... yes
checking for wcsxfrm... yes
checking for wmemcmp... yes
checking for writev... yes
checking for _getpty... no
checking whether dirfd is declared... yes
checking for chroot... yes
checking for link... yes
checking for symlink... yes
checking for fchdir... yes
checking for fsync... yes
checking for fdatasync... yes
checking for epoll... yes
checking for epoll_create1... yes
checking for kqueue... no
checking for prlimit... yes
checking for ctermid_r... no
checking for flock declaration... yes
checking for flock... yes
checking for getpagesize... yes
checking for broken unsetenv... no
checking for true... true
checking for inet_aton in -lc... yes
checking for chflags... no
checking for lchflags... no
checking for inflateCopy in -lz... no
checking for hstrerror... yes
checking for inet_aton... yes
checking for inet_pton... yes
checking for setgroups... yes
checking for openpty... no
checking for openpty in -lutil... yes
checking for forkpty... yes
checking for memmove... yes
checking for fseek64... no
checking for fseeko... yes
checking for fstatvfs... yes
checking for ftell64... no
checking for ftello... yes
checking for statvfs... yes
checking for dup2... yes
checking for strdup... yes
checking for getpgrp... yes
checking for setpgrp... (cached) yes
checking for gettimeofday... yes
checking for clock_gettime... yes
checking for clock_getres... yes
checking for clock_settime... yes
checking for major... yes
checking for if_nameindex... yes
checking for lockf... yes
checking for getaddrinfo... yes
checking getaddrinfo bug... no
checking for getnameinfo... yes
checking whether time.h and sys/time.h may both be included... yes
checking whether struct tm is in sys/time.h or time.h... time.h
checking for struct tm.tm_zone... yes
checking for struct stat.st_rdev... yes
checking for struct stat.st_blksize... yes
checking for struct stat.st_flags... no
checking for struct stat.st_gen... no
checking for struct stat.st_birthtime... no
checking for struct stat.st_blocks... yes
checking for struct passwd.pw_gecos... yes
checking for struct passwd.pw_passwd... yes
checking for time.h that defines altzone... no
checking whether sys/select.h and sys/time.h may both be included... yes
checking for addrinfo... yes
checking for sockaddr_storage... yes
checking for sockaddr_alg... yes
checking whether char is unsigned... no
checking for an ANSI C-conforming const... yes
checking for working volatile... yes
checking for working signed char... yes
checking for prototypes... yes
checking for variable length prototypes and stdarg.h... yes
checking for socketpair... yes
checking if sockaddr has sa_len member... no
checking for gethostbyname_r... yes
checking gethostbyname_r with 6 args... yes
checking for __fpu_control... yes
checking for --with-fpectl... no
checking for --with-libm=STRING... default LIBM="-lm"
checking for --with-libc=STRING... default LIBC=""
checking for x64 gcc inline assembler... yes
checking whether C doubles are little-endian IEEE 754 binary64... yes
checking whether C doubles are big-endian IEEE 754 binary64... no
checking whether C doubles are ARM mixed-endian IEEE 754 binary64... no
checking whether we can use gcc inline assembler to get and set x87 control word... yes
checking whether we can use gcc inline assembler to get and set mc68881 fpcr... no
checking for x87-style double rounding... no
checking for acosh... yes
checking for asinh... yes
checking for atanh... yes
checking for copysign... yes
checking for erf... yes
checking for erfc... yes
checking for expm1... yes
checking for finite... yes
checking for gamma... yes
checking for hypot... yes
checking for lgamma... yes
checking for log1p... yes
checking for log2... yes
checking for round... yes
checking for tgamma... yes
checking whether isinf is declared... yes
checking whether isnan is declared... yes
checking whether isfinite is declared... yes
checking whether tanh preserves the sign of zero... yes
checking whether log1p drops the sign of negative zero... no
checking whether POSIX semaphores are enabled... yes
checking for broken sem_getvalue... no
checking whether RTLD_LAZY is declared... yes
checking whether RTLD_NOW is declared... yes
checking whether RTLD_GLOBAL is declared... yes
checking whether RTLD_LOCAL is declared... yes
checking whether RTLD_NODELETE is declared... yes
checking whether RTLD_NOLOAD is declared... yes
checking whether RTLD_DEEPBIND is declared... yes
checking digit size for Python's longs... no value specified
checking wchar.h usability... yes
checking wchar.h presence... yes
checking for wchar.h... yes
checking size of wchar_t... 4
checking for UCS-4 tcl... no
checking whether wchar_t is signed... yes
no usable wchar_t found
checking whether byte ordering is bigendian... no
checking ABIFLAGS... m
checking SOABI... cpython-36m-x86_64-linux-gnu
checking LDVERSION... $(VERSION)$(ABIFLAGS)
checking whether right shift extends the sign bit... yes
checking for getc_unlocked() and friends... yes
checking how to link readline libs... none
checking for rl_callback_handler_install in -lreadline... no
checking for rl_pre_input_hook in -lreadline... no
checking for rl_completion_display_matches_hook in -lreadline... no
checking for rl_resize_terminal in -lreadline... no
checking for rl_completion_matches in -lreadline... no
checking for append_history in -lreadline... no
checking for broken nice()... no
checking for broken poll()... no
checking for struct tm.tm_zone... (cached) yes
checking for working tzset()... yes
checking for tv_nsec in struct stat... yes
checking for tv_nsec2 in struct stat... no
checking curses.h usability... no
checking curses.h presence... no
checking for curses.h... no
checking ncurses.h usability... no
checking ncurses.h presence... no
checking for ncurses.h... no
checking for term.h... no
checking whether mvwdelch is an expression... no
checking whether WINDOW has _flags... no
checking for is_term_resized... no
checking for resize_term... no
checking for resizeterm... no
configure: checking for device files
checking for /dev/ptmx... yes
checking for /dev/ptc... no
checking for %zd printf() format support... yes
checking for socklen_t... yes
checking for broken mbstowcs... no
checking for --with-computed-gotos... no value specified
checking whether gcc -pthread supports computed gotos... yes
checking for build directories... done
checking for -O2... yes
checking for glibc _FORTIFY_SOURCE/memmove bug... no
checking for gcc ipa-pure-const bug... no
checking for stdatomic.h... no
checking for GCC >= 4.7 __atomic builtins... yes
checking for ensurepip... upgrade
checking if the dirent structure of a d_type field... yes
checking for the Linux getrandom() syscall... yes
checking for the getrandom() function... no
configure: creating ./config.status
config.status: creating Makefile.pre
config.status: creating Modules/Setup.config
config.status: creating Misc/python.pc
config.status: creating Misc/python-config.sh
config.status: creating Modules/ld_so_aix
config.status: creating pyconfig.h
creating Modules/Setup
creating Modules/Setup.local
creating Makefile
If you want a release build with all stable optimizations active (PGO, etc),
please run ./configure --enable-optimizations
Step 4.
Now run make followed by make install to complete the installation. Both commands output is not given here since its pretty long.
root@kerneltalks # make
root@kerneltalks # make install
Step 5.
Check Python installed version from Python prompt.
root@kerneltalks # python3
Python 3.6.3 (default, Nov 5 2017, 12:28:06)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-16)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
You can see in the above output Python 3.6.3 shows we have installed python v3 successfully.
Troubleshooting Python issues
When using or compiling Python programs you might run into below errors. I have listed their solutions for your quick reference.
Error : ImportError: No module named 'zlib'
Solution:Install zlib-devel (zlib development tools) package and re-install python
Error : ImportError: cannot import name 'HTTPSConnection'
Solution: Install OpenSSL-devel (Open SSL development tools) package and re-install python
Error : zipimport.ZipImportError: can't decompress data; zlib not available
Solution: This error is seen during Python installation if zlib is not installed on the server. Install zlib package
Learn about huge pages in Linux. Understand what is huge pages, how to configure it, how to check the current state, and how to disable it.
HugePages in Linux
In this article, we will walk you through details about huge pages so that you will be able to answer: what are huge pages in Linux? How to enable/disable huge pages? How to determine huge page value? in Linux like RHEL6, RHEL7, Ubuntu, etc.
Lets start with Huge pages basics.
What is Huge page in Linux?
Huge pages are helpful in virtual memory management in the Linux system. As the name suggests, they help is managing huge size pages in memory in addition to standard 4KB page size. You can define as huge as 1GB page size using huge pages.
During system boot, you reserve your memory portion with huge pages for your application. This memory portion i.e. these memory occupied by huge pages is never swapped out of memory. It will stick there until you change your configuration. This increases application performance to a great extent like Oracle database with pretty large memory requirements.
Why use huge page?
In virtual memory management, the kernel maintains a table in which it has a mapping of the virtual memory address to a physical address. For every page transaction, the kernel needs to load related mapping. If you have small size pages then you need to load more numbers of pages resulting kernel to load more mapping tables. This decreases performance.
Using huge pages means you will need fewer pages. This decreases the number of mapping tables to load by the kernel to a great extent. This increases your kernel-level performance which ultimately benefits your application.
In short, by enabling huge pages, the system has fewer page tables to deal with and hence less overhead to access/maintain them!
How to configure huge pages?
Run below command to check current huge pages details.
In the above output, you can see the one-page size is 2MB Hugepagesize and a total of 0 pages on the system HugePages_Total. This huge page size can be increased from 2MB to max 1GB.
Run below script to get how much huge pages your system needs currently. The script is from Oracle and can be found.
#!/bin/bash
#
# hugepages_settings.sh
#
# Linux bash script to compute values for the
# recommended HugePages/HugeTLB configuration
#
# Note: This script does calculation for all shared memory
# segments available when the script is run, no matter it
# is an Oracle RDBMS shared memory segment or not.
# Check for the kernel version
KERN=`uname -r | awk -F. '{ printf("%d.%d\n",$1,$2); }'`
# Find out the HugePage size
HPG_SZ=`grep Hugepagesize /proc/meminfo | awk {'print $2'}`
# Start from 1 pages to be on the safe side and guarantee 1 free HugePage
NUM_PG=1
# Cumulative number of pages required to handle the running shared memory segments
for SEG_BYTES in `ipcs -m | awk {'print $5'} | grep "[0-9][0-9]*"`
do
MIN_PG=`echo "$SEG_BYTES/($HPG_SZ*1024)" | bc -q`
if [ $MIN_PG -gt 0 ]; then
NUM_PG=`echo "$NUM_PG+$MIN_PG+1" | bc -q`
fi
done
# Finish with results
case $KERN in
'2.4') HUGETLB_POOL=`echo "$NUM_PG*$HPG_SZ/1024" | bc -q`;
echo "Recommended setting: vm.hugetlb_pool = $HUGETLB_POOL" ;;
'2.6' | '3.8' | '3.10' | '4.1' ) echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;;
*) echo "Unrecognized kernel version $KERN. Exiting." ;;
esac
# End
You can save it in /tmp as hugepages_settings.sh and then run it like below :
root@kerneltalks # sh /tmp/hugepages_settings.sh
Recommended setting: vm.nr_hugepages = 124
Output will be similar to some number as shown in above sample output.
This means your system needs 124 huge pages of 2MB each! If you have set 4MB as page size then the output would have been 62. You got the point, right?
Configure hugepages in kernel
Now last part is to configure the above-stated kernel parameter and reload it. Add below value in /etc/sysctl.conf and reload configuration by issuing sysctl -p command.
vm.nr_hugepages=126
Notice that we added 2 extra pages in the kernel since we want to keep a couple of pages spare than the actual required number.
Now, huge pages have been configured in the kernel but to allow your application to use them you need to increase memory limits as well. The new memory limit should be 126 pages x 2 MB each = 252 MB i.e. 258048 KB.
You need to edit below settings in /etc/security/limits.conf
soft memlock 258048
hard memlock 258048
Sometimes these settings are configured in app-specific files like for Oracle DB its in /etc/security/limits.d/99-grid-oracle-limits.conf
That’s it! You might want to restart your application to make use of these new huge pages.
How to disable hugepages?
HugePages are generally enabled by default. Use the below command to check the current state of huge pages.
root@kerneltalks # cat /sys/kernel/mm/transparent_hugepage/enabled
[always] madvise never
[always] flag in output shows that hugepages are enabled on system.
For RedHat based systems file path is /sys/kernel/mm/redhat_transparent_hugepage/enabled
If you want to disable huge pages then add transparent_hugepage=never at the end of kernel line in /etc/grub.conf and reboot the system.
Article explaining ‘ERROR Cannot fetch deployment URL via curl: Couldn’t resolve host. The given remote host was not resolved.’ and how to resolve it.
check_mk register error
check_mk is a utility that helps you configure your server to be monitored via nagios monitoring tool. While configuring one of the clients I came across below error :
ERROR Cannot fetch deployment URL via curl: Couldn't resolve host. The given remote host was not resolved.
This error came after I tried to register the client with the monitoring server with below command :
-s is monitoring server -i is Name of Check_MK site on that server -H is Hostname to fetch agent for -p is protocol Either HTTP or HTTPS (default is HTTPS) -U User-ID of a user who is allowed to download the agent. -S is secret. Automation secret of that user (in case of automation user) From the error, you can figure out that command is not able to resolve to monitor server DNS name monitor.kerneltalks.com
Solution
Its pretty simple. Check /etc/resolv.conf to make sure that you have proper DNS server entry for your environment. If it still doesn’t resolve the issue then you can add an entry in /etc/hosts for it.
Thats it. You would be able to register now successfully.
root@kerneltalks # /usr/bin/cmk-update-agent register -s monitor.kerneltalks.com -i master -H `hostname` -p http -U omdadmin -S ASFKWEFUNSHEFKG -v
Going to register agent at deployment server
Successfully registered agent for deployment.
You can now update your agent by running 'cmk-update-agent -v'
Saved your registration settings to /etc/cmk-update-agent.state.
By the way, you can directly use the IP address for -s switch and get rid of all the above jargon including error itself!
Troubleshooting error ‘mount.nfs: requested NFS version or transport protocol is not supported’ and how to resolve it.
Resolve NFS error
Another troubleshooting article aimed at specific errors and help you how to solve it. In this article, we will see how to resolve error ‘mount.nfs: requested NFS version or transport protocol is not supported’ seen on NFS client while trying to mount NFS share.
# mount 10.0.10.20:/data /data_on_nfs
mount.nfs: requested NFS version or transport protocol is not supported
Sometimes you see error mount.nfs: requested NFS version or transport protocol is not supported when you try to mount NFS share on NFS client. There are couple of reasons you see this error :
NFS services are not running on NFS server
NFS utils not installed on the client
NFS service hung on NFS server
NFS services at the NFS server can be down or hung due to multiple reasons like server utilization, server reboot, etc.
To get rid of this error and successfully mount your share follow the below steps.
Login to the NFS server and check the NFS services status.
[root@kerneltalks]# service nfs status
rpc.svcgssd is stopped
rpc.mountd is stopped
nfsd is stopped
rpc.rquotad is stopped
In the above output you can see the NFS services are stopped on the server. Start them.
[root@kerneltalks]# service nfs start
Starting NFS services: [ OK ]
Starting NFS quotas: [ OK ]
Starting NFS mountd: [ OK ]
Starting NFS daemon: [ OK ]
Starting RPC idmapd: [ OK ]
You might want to check for nfs-server or nfsserver service as well depends on your Linux distro.
Now try to mount NFS share on the client. And you will be able to mount them using the same command we see earlier!
Solution 2 :
If that doesn’t work for you then try installing package nfs-utils on your server and you will get through this error.
Solution 3 :
Open file /etc/sysconfig/nfs and try to check below parameters
# Turn off v4 protocol support
#RPCNFSDARGS="-N 4"
# Turn off v2 and v3 protocol support
#RPCNFSDARGS="-N 2 -N 3"
Removing hash from RPCNFSDARGS lines will turn off specific version support. This way clients with mentioned NFS versions won’t be able to connect to the NFS server for mounting share. If you have any of it enabled, try disabling it and mounting at the client after the NFS server service restarts.
Let us know if you have faced this error and solved it by any other methods in the comments below. We will update our article with your information to keep it updated and help the community live better!
Learn how to use speedtest CLI tool to test internet speed in the Linux terminal. It also includes a one-liner python command to get speed details right away.
Internet speed check in Linux
Most of us check the internet bandwidth speed whenever we connect to a new network or wifi. So why not our servers! Here is a tutorial that will walk you through to test internet speed in the Linux terminal.
Every one of us generally uses Speedtest by Ookla to check internet speed. It’s a pretty simple process for a desktop. Go to their website and just click the GO button. It will scan your location and speed test with the nearest server. If you are on mobile, they have their app for you. But if you are on the terminal with command-line interface things are little different. Let’s see how to check internet speed from the Linux terminal.
If you want to speed check only once and don’t want to download the tool on the server, jump here and see one-liner command.
Step 1 : Download speedtest cli tool
First of all, you have to download speedtest CLI tool from the GitHub repository. Nowadays, it also included in many well known Linux repositories as well. If it’s there then you can directly install that package on your Linux distro.
Let’s proceed with the Github download and install process. Install the git package depending on your distro. Then clone Github repo of speedtest like below:
It will be cloned to your present working directory. A new directory named speedtest-cli will be created. You can see the below files in it.
[root@kerneltalks ~]# cd speedtest-cli
[root@kerneltalks speedtest-cli]# ll
total 96
-rw-r--r--. 1 root root 1671 Oct 7 16:55 CONTRIBUTING.md
-rw-r--r--. 1 root root 11358 Oct 7 16:55 LICENSE
-rw-r--r--. 1 root root 35 Oct 7 16:55 MANIFEST.in
-rw-r--r--. 1 root root 5215 Oct 7 16:55 README.rst
-rw-r--r--. 1 root root 20 Oct 7 16:55 setup.cfg
-rw-r--r--. 1 root root 3196 Oct 7 16:55 setup.py
-rw-r--r--. 1 root root 2385 Oct 7 16:55 speedtest-cli.1
-rw-r--r--. 1 root root 1200 Oct 7 16:55 speedtest_cli.py
-rwxr-xr-x. 1 root root 47228 Oct 7 16:55 speedtest.py
-rw-r--r--. 1 root root 333 Oct 7 16:55 tox.ini
The python script speedtest.py is the one we will be using to check internet speed.
You can link this script for a command in /usr/bin so that all users on the server can use it. Or you can even create command alias for it and it will be easy for all users to use it.
Step 2 : Run python script
Now, run a python script without any argument and it will search the nearest server and test your internet speed.
[root@kerneltalks speedtest-cli]# python speedtest.py
Retrieving speedtest.net configuration...
Testing from Amazon (35.154.184.126)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by Spectra (Mumbai) [1.15 km]: 8.174 ms
Testing download speed................................................................................
Download: 548.13 Mbit/s
Testing upload speed................................................................................................
Upload: 323.95 Mbit/s
You can see here, the first column is a server identifier followed by the name of the company hosting that server, location, and finally its distance from your location.
To test the internet speed using specific server use --server switch and server identifier from the previous output as an argument.
[root@kerneltalks speedtest-cli]# python speedtest.py --server 2827
Retrieving speedtest.net configuration...
Testing from Amazon (35.154.184.126)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by Bharti Airtel Ltd (Mumbai) [1.15 km]: 13.234 ms
Testing download speed................................................................................
Download: 93.47 Mbit/s
Testing upload speed................................................................................................
Upload: 69.25 Mbit/s
To get the share link of your speed test, use –share switch. It will give you the URL of your test hosted on speedtest website. You can share this URL.
[root@kerneltalks speedtest-cli]# python speedtest.py --share
Retrieving speedtest.net configuration...
Testing from Amazon (35.154.184.126)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by Spectra (Mumbai) [1.15 km]: 7.471 ms
Testing download speed................................................................................
Download: 621.00 Mbit/s
Testing upload speed................................................................................................
Upload: 367.37 Mbit/s
Share results: http://www.speedtest.net/result/6687428141.png
Observe the last line which includes the URL of your test result. If I download that image its the one below :
Speedtest result on Linux
That’s it! But hey if you don’t want all this technical jargon, you can even use below one-liner to get speed test done right away.
Internet speed test using one liner in terminal
We are going to use a curl tool to fetch the above python script online and supply it to python for execution on the go!
Understand and learn about data center tier. The article explains the data center standardization matrix: tier 1 to tier 4 along with its eligibility criteria.
Data center tiers
Most of our readers are system administrators and surely come across term call data center tiers in their sysadmin life. This article will walk you through what is data center tiers? Different types of data center tiers, what is tier 1, tier 2, tier 3, and tier 4 data center? Which tier data center have maximum availability? etc.
All these might be interview questions for system architects at the beginner level. As a sysadmin its always good to know data center tiers so that you are well verse with your company infrastructure and can decide if that can really deliver on SLAs defined in your environment.
Without further delay, lets start with our topic.
What is data center tier?
Datacenter tier is the standardization matrix that defines overall performance, availability, fault tolerance capability, operating environment of a data center. It defines how the data center is fault-tolerant, how it can sustain to failures of various components, power, connectivity links, etc. It defines availability being offered for hosted servers.
Basically data center tier helps customers to determine which tier is best suitable for their application depending on the SLA requirement and data critical index they have. Mission-critical services should be hosted under a higher tier data center whereas less critical data should be hosted in lower-tier data centers. Obviously cost is another factor here too. As you go on high with tier, cost increases for hosting.
Different data center tiers
There are 4 data center tier standards defined by Uptime Institute. They are as below :
Tier 1: Non-redundant capacity and single power, connectivity distribution
Tier 2: Tier 1 feature + redundant capacity
Tier 3: Tier 2 features + Multiple independent power, connectivity distribution + onsite energy production system
Tier 4: Tier 3 features + All components are fault-tolerant, continuous cooling equipment.
A detailed list of requirements to be fulfilled by the data center to be eligible for specific tier is available here.
Data center tier deciding factors :
Datacenter to be eligible for certain tier it should complete certain criteria (as we saw above). There are many factors that affect/help in achieving those criteria. These factors are as below –
Datacenter design, location
Mechanical infrastructure design
Technology infrastructure design
Electric power distribution
Cables distribution
Network and internet connectivity distribution
Fire protection
Security in terms of soft security and physical security controls like biometric etc
Energy production, use, efficiency
Waste management
Environmental control and effects
Cooling management
Capacity management
Accepted downtime and availability tier wise
Tier 1: 99.671% uptime, 28.8 hours downtime per year
Tier 2: 99.749% uptime, 22 hours downtime per year
Tier 3: 99.982% uptime, 1.6 hours downtime per year
Tier 4: 99.995% uptime, 26.3 minutes downtime per year
That’s all I have to share with you about data center tier standards. Feel free to point out mistakes, suggestions, feedback in the comments section below.
