Linux Services
Programs that run in the background, provide various functionalities and services to the system and other applications.
Infrastructure
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A brief description of commands is given in Essential Linux Commands.
Task Details
As per details shared by the development team, the new application release has some dependencies on the back end.
There are some packages/services that need to be installed on all app servers under Stratos Datacenter. As per requirements please perform the following steps.
a. Install the squid package on all the application servers.
b. Once installed, make sure it is enabled to start during boot.
Perform the below commands based on your question server, user name & other details that might differ as per the task.
Solution:
1. At first login on App server & Switch to the root user
thor@jump_host ~$ ssh tony@stapp01
The authenticity of host 'stapp01 (172.16.238.10)' can't be established.
ECDSA key fingerprint is SHA256:BEmbndWZwybHvgohbP2hOAD0j2ErgvbEi3IpLZuaOKU.
ECDSA key fingerprint is MD5:27:54:d2:2f:14:bf:27:b6:4a:70:ac:a7:34:1d:c2:cb.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'stapp01,172.16.238.10' (ECDSA) to the list of known hosts.
tony@stapp01's password:
[tony@stapp01 ~]$ sudo su -
We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:
#1) Respect the privacy of others.
#2) Think before you type.
#3) With great power comes great responsibility.
[sudo] password for tony:
[root@stapp01 ~]#
2. Install the squid service package ( refer to your task )
[root@stapp01 ~]# yum install squid -y
Loaded plugins: fastestmirror, ovl
Determining fastest mirrors
* base: atl.mirrors.clouvider.net
* extras: mirrors.gigenet.com
* updates: mirrors.liquidweb.com
base | 3.6 kB 00:00:00
extras | 2.9 kB 00:00:00
updates | 2.9 kB 00:00:00
(1/4): extras/7/x86_64/primary_db | 242 kB 00:00:00
(2/4): base/7/x86_64/group_gz | 153 kB 00:00:00
(3/4): base/7/x86_64/primary_db | 6.1 MB 00:00:00
(4/4): updates/7/x86_64/primary_db | 8.8 MB 00:00:00
Resolving Dependencies
--> Running transaction check
---> Package squid.x86_64 7:3.5.20-17.el7_9.6 will be installed
--> Processing Dependency: squid-migration-script for package: 7:squid-3.5.20-17.el7_9.6.x86_64
Verifying : perl-Digest-1.17-245.el7.noarch 40/41
Verifying : 4:perl-libs-5.16.3-299.el7_9.x86_64 41/41
Installed:
squid.x86_64 7:3.5.20-17.el7_9.6
Dependency Installed:
perl-Exporter.noarch 0:5.68-3.el7 perl-File-Path.noarch 0:2.09-2.el7 perl-File-Temp.noarch 0:0.23.01-3.el7
perl-Filter.x86_64 0:1.49-3.el7 perl-Getopt-Long.noarch 0:2.40-3.el7 perl-HTTP-Tiny.noarch 0:0.033-3.el7
perl-IO-Compress.noarch 0:2.061-2.el7 perl-Net-Daemon.noarch 0:0.48-5.el7 perl-PathTools.x86_64 0:3.40-5.el7
perl-PlRPC.noarch 0:0.2020-14.el7 perl-Pod-Escapes.noarch 1:1.04-299.el7_9 perl-Pod-Perldoc.noarch 0:3.20-4.el7
perl-Pod-Simple.noarch 1:3.28-4.el7 perl-Pod-Usage.noarch 0:1.63-3.el7 perl-Scalar-List-Utils.x86_64 0:1.27-248.el7
perl-Socket.x86_64 0:2.010-5.el7 perl-Storable.x86_64 0:2.45-3.el7 perl-Text-ParseWords.noarch 0:3.29-4.el7
perl-Time-HiRes.x86_64 4:1.9725-3.el7 perl-Time-Local.noarch 0:1.2300-2.el7 perl-constant.noarch 0:1.27-2.el7
perl-libs.x86_64 4:5.16.3-299.el7_9 perl-macros.x86_64 4:5.16.3-299.el7_9 perl-parent.noarch 1:0.225-244.el7
perl-podlators.noarch 0:2.5.1-3.el7 perl-threads.x86_64 0:1.87-4.el7 perl-threads-shared.x86_64 0:1.43-6.el7
squid-migration-script.x86_64 7:3.5.20-17.el7_9.6
Complete!
[root@stapp01 ~]#
3. Start & enable the service
[root@stapp01 ~]# systemctl start squid
[root@stapp01 ~]# systemctl enable squid
Created symlink from /etc/systemd/system/multi-user.target.wants/squid.service to /usr/lib/systemd/system/squid.service.
[root@stapp01 ~]#
4. Validate the task
[root@stapp01 ~]# systemctl status squid
● squid.service - Squid caching proxy
Loaded: loaded (/usr/lib/systemd/system/squid.service; enabled; vendor preset: disabled)
Active: active (running) since Sat 2021-06-26 15:06:48 UTC; 1min 37s ago
Main PID: 907 (squid)
CGroup: /docker/10d9c7b82ed12cacb53bddf6953c3da3d792077999899e21e6b3f0057bffa04c/system.slice/squid.service
├─907 /usr/sbin/squid -f /etc/squid/squid.conf
├─909 (squid-1) -f /etc/squid/squid.conf
└─910 (logfile-daemon) /var/log/squid/access.log
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com systemd[906]: Executing: /usr/sbin/squid -f /etc/squid/squid.conf
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com squid[907]: Squid Parent: will start 1 kids
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com squid[907]: Squid Parent: (squid-1) process 909 started
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com systemd[1]: Child 906 belongs to squid.service
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com systemd[1]: squid.service: control process exited, code=exited status=0
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com systemd[1]: squid.service got final SIGCHLD for state start
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com systemd[1]: Main PID guessed: 907
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com systemd[1]: squid.service changed start -> running
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com systemd[1]: Job squid.service/start finished, result=done
Jun 26 15:06:48 stapp01.stratos.xfusioncorp.com systemd[1]: Started Squid caching proxy.
[root@stapp01 ~]#
I have shown only for stapp01. You have to do this in all app server stapp01, stapp02, stapp03.
Thank you so much for taking your valuable time to read
I took the initiative to learn in public and share my work with others. I tried my level best in squeezing as much information as possible in the easiest manner. Hope you learned something new today :)
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