Ansible Installation / Ubuntu 18.04 Environment

1. Installation Environment

[Figure 1] Node configuration diagram for Ansible installation

Ubuntu 18.04 LTS 64bit, root user
Ansible 2.5.1

2. Ansible Installation

(Control)$ apt-get install software-properties-common
(Control)$ apt-add-repository ppa:ansible/ansible
(Control)$ apt-get update
(Control)$ apt-get install ansible

Install Ansible on Control Node.

3. Inventory Configuration

1
2
3
[cluster]
172.35.0.101
172.35.0.102

[File 1] Control Node - /etc/ansible/hosts

Store Managed Node IP information in Control Node’s /etc/ansible/hosts file as shown in [File 1].

4. SSH Key Generation and Configuration

(Control)$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id-rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id-rsa.
Your public key has been saved in /root/.ssh/id-rsa.pub.
The key fingerprint is:
SHA256:Sp0SUDPNKxTIYVObstB0QQPoG/csF9qe/v5+S5e8hf4 root@kube02
The key's randomart image is:
+---[RSA 2048]----+
||   oBB@=         |
||  .+o+.*o        |
|| .. o.+  .       |
||  o..ooo..       |
||   +.=ooS        |
||  . o.=o     . o |
||     +..    . = .|
||      o    ..o o |
||     ..oooo...o.E|
+----[SHA256]-----+

Generate ssh key on Control Node. Enter blank for passphrase (Password) to not set it. If set, you need to enter passphrase every time accessing Managed Node from Control Node via SSH.

(Control)$ ssh-copy-id root@172.35.0.101 
(Control)$ ssh-copy-id root@172.35.0.102

Use ssh-copy-id command from Control Node to copy generated ssh Public Key to all Managed Nodes’ ~/.ssh/authorized-keys files.

5. Ansible Operation

(Control)$ ansible all -m ping
172.35.0.101 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
172.35.0.102 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}

Use ansible all -m ping command from Control Node to verify that SSH connection from Control Node to Managed Node is possible.

6. References

https://docs.ansible.com/ansible/latest/installation-guide/index.html

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