Understanding Ad-hoc commands in Ansible
Day 56 and Day 57 of #90daysofdevops challenge
Table of contents
- What are Ad hoc commands?
- Task-01: Write an ansible ad hoc ping command to ping 2 servers from the inventory file
- Task-02: Write an ansible ad hoc command to check uptime
- Task-03: Ansible ad hoc command to check the free Ram memory or memory usage of hosts.
- Task-04: Write an ansible ad hoc command to check the disk space on all hosts in an inventory file.
- Task-05: Write an ansible ad hoc command to list all the running processes on a specific host in an inventory file.
What are Ad hoc commands?
Ansible ad hoc commands are one-liners designed to achieve a very specific task they are like quick snippets and your compact swiss army knife when you want to do a quick task across multiple machines.
To put simply, Ansible ad hoc commands are one-liner Linux shell commands and playbooks are like a shell script, a collective of many commands with logic.
Ansible ad hoc commands come in handy when you want to perform a quick task.
Task-01: Write an ansible ad hoc ping command to ping 2 servers from the inventory file
We have already created EC2 instances and made a connection between them. Check out this blog for a better understanding:
- Let's start the instances.
- Now connect to the Master instance and ping the 2 servers.
Task-02: Write an ansible ad hoc command to check uptime
To check the uptime of a remote server using Ansible's ad hoc command, you can use the ansible command with the -a option for the uptime command. Here's the command and an explanation of each part:
ansible <target_host> -m command -a uptime
<target_host>: Replace this with the hostname or IP address of the remote server you want to check the uptime for.-m command: This specifies the Ansible module to use. In this case, we're using thecommandmodule, which allows us to execute a shell command on the remote host.-a "uptime": This is the argument passed to thecommandmodule. It specifies the shell command to run on the remote host, which is simply "uptime" in this case.
Task-03: Ansible ad hoc command to check the free Ram memory or memory usage of hosts.
ansible <target_host> all -a "free -m"
Task-04: Write an ansible ad hoc command to check the disk space on all hosts in an inventory file.
ansible <target_host> all -m shell -a "df -h"
Task-05: Write an ansible ad hoc command to list all the running processes on a specific host in an inventory file.
ansible <target_host> specific_host -m command -a 'ps aux'
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