Using ansible to manage instances on flex cloud
In this blog post we will discuss how we can use ansible to manage instances running on a flex cloud. It is important to note that while it is possible to create resources on an openstack cloud using ansible itself but the main aim of this blog post is to discuss how we can manage existing instances running within a project with ansible. The examples provided in this blog post are for instances running ubuntu 20.04 LTS as the base OS; these instructions can be adapted to accomodate any other OS as well
The blog post assumes that the the node from where we are running the openstack and ansible commands has network access to the flex cloud and the credentions for a valid user in the flex cloud are sourced and ansible is installed on the node from where the ansible playbooks and adhoc commands will run. The bootstrap script in the install guide creates the venv with the necessary components installed inside the venv
The first step in this process is to gather the required details for generating the ansible inventory for our instances; For the example presented in this blog post there are 2 instances which have floating ip(s) assigned to them and the floating ip(s) are reachable from the bastion host from where the ansible adhoc commands and ansible playbooks will run
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To generate the inventory for the existing instances within a project capture the list of running instances:
(genestack) root@bastn:~# openstack server list +--------------------------------------+--------------+--------+---------------------------------+----------+-----------+ | ID | Name | Status | Networks | Image | Flavor | +--------------------------------------+--------------+--------+---------------------------------+----------+-----------+ | 94e7b2eb-a3b1-4f48-9e86-70f463e7e8bd | test-epsilon | ACTIVE | net1=10.10.10.151, 172.16.8.94 | ubuntu20 | m1.medium | | 9f8b7596-c332-4000-8154-650d5a2e95fd | test-alpha | ACTIVE | net1=10.10.10.139, 172.16.8.170 | ubuntu20 | m1.medium | +--------------------------------------+--------------+--------+---------------------------------+----------+-----------+ -
Then we will need the fixed ip(s) assigned to the running instances:
(genestack) root@bastn:~# for i in $(openstack server list -c ID -f value); do openstack port list --server $i -c "Fixed IP Addresses" -f value; done [{'subnet_id': 'd31a8c8b-e8f5-47fa-9d2e-0d30df2fd37c', 'ip_address': '172.16.8.94'}] [{'subnet_id': 'd31a8c8b-e8f5-47fa-9d2e-0d30df2fd37c', 'ip_address': '172.16.8.170'}] -
With the fixed ip(s) for the ports associated with the instances we can capture the floating ip(s) associated with these instances:
(genestack) root@bastn:~# for i in 172.16.8.94 172.16.8.170; do openstack floating ip list --fixed-ip-address $i -f yaml; done - Fixed IP Address: 172.16.8.94 Floating IP Address: 10.10.10.151 Floating Network: c03d6556-d7cb-44c6-a0cd-2985c47ddcfd ID: 2f1163f2-46c7-4092-8755-db0542ec2383 Port: f6051f7f-c2b4-4803-9453-3ac67da27c55 Project: 7d9c7a46b38d40b891dd0c40644773ee - Fixed IP Address: 172.16.8.170 Floating IP Address: 10.10.10.139 Floating Network: c03d6556-d7cb-44c6-a0cd-2985c47ddcfd ID: 58ff2b9e-1ebb-475a-b60a-f645aa72b75f Port: 7fe428be-4fe0-4e09-ae0d-3aea09c1ccf4 Project: 7d9c7a46b38d40b891dd0c40644773ee -
With the floating ip(s) listed we can create a simple inventory.ini inventory file for ansible:
It should be noted that in this case the ansible_ssh_user is set to ubuntu this is because it is the default in the cloud images for Ubuntu OS and the ubuntu user has sudo privileges which are required by ansible to execute the tasks on the instances -
With the inventory created we can try to run the ping module to test whether ansible can reach the instances on the flex cloud:
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We can see that the ping succeeded and now to install apache2 package on test-epsilon instance with ansible using an adhoc command:
In this example we can see that we can easily install apache2 package on the instance named test-epsilon by referring to it's group name in the inventory -
Let's say that we would like to run a full playbook against the instance named test-alpha running on the flex cloud; the example playbook in this case installs apache2 package on the instance and configures a custom homepage for the guest; for this purpose we will first need to create the playbook and the jinja file:
main.yml(genestack) root@bastn:~# cat main.yml --- - name: Playbook to install apache on Ubuntu instances on flex cloud hosts: alpha gather_facts: true tasks: - name: update apt cache on the ubuntu guest ansible.builtin.apt: update_cache: yes - name: install the apache package on the guest ansible.builtin.apt: name: apache2 state: present - name: enable and start apache2 service on the guest ansible.builtin.service: name: apache2 enabled: yes state: started - name: copy the custom index.html file to the document root on the guest template: src: index.html.j2 dest: /var/www/html/index.html notify: - restart apache2 service handlers: - name: restart apache2 service ansible.builtin.service: name: apache2 state: restarted -
We can then run the playbook which installs apache2 package on the test-alpha instances and configures a custom homepage for the webserver running inside the guest:
It should be noted that in this case the ansible-key is the key with which the instances were created and the same key is provided to ansible(genestack) root@bastn:~# ansible-playbook --inventory inventory.ini main.yml --private-key ansible-key --become PLAY [Playbook to install apache on Ubuntu instances on flex cloud] ******************************************************************************************************************************************* TASK [Gathering Facts] **************************************************************************************************************************************************************************************** ok: [test-alpha] TASK [update apt cache on the ubuntu guest] ******************************************************************************************************************************************************************* changed: [test-alpha] TASK [install the apache package on the guest] **************************************************************************************************************************************************************** changed: [test-alpha] TASK [enable and start apache2 service on the guest] ********************************************************************************************************************************************************** ok: [test-alpha] TASK [copy the custom index.html file to the document root on the guest] ************************************************************************************************************************************** changed: [test-alpha] RUNNING HANDLER [restart apache2 service] ********************************************************************************************************************************************************************* changed: [test-alpha] PLAY RECAP **************************************************************************************************************************************************************************************************** test-alpha : ok=6 changed=4 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0