Ansible search for a substring in stdout output - ansible

Question

Team,
I am trying to match a version and that fails when whole string does not match. so I just want to match first two octects. I tried several combons but no luck.
- name: "Validate k8s version"
shell: "kubectl version --short"
register: k8s_version_live
failed_when: k8s_version_live.stdout_lines is not search("{{ k8s_server_version }}")
#failed_when: "'{{ k8s_server_version }}' not in k8s_version_live.stdout_lines"
ignore_errors: yes
- debug:
var: k8s_version_live.stdout_lines
output:
[WARNING]: conditional statements should not include jinja2 templating delimiters such as {{ }} or {% %}. Found: k8s_version_live.stdout_lines is not search("{{
k8s_server_version }}")
fatal: [localhost]: FAILED! => {"changed": true, "cmd": "kubectl version --short", "delta": "0:00:00.418128", "end": "2019-12-05 02:13:15.108997", "failed_when_result": true, "rc": 0, "start": "2019-12-05 02:13:14.690869", "stderr": "", "stderr_lines": [], "stdout": "Client Version: v1.13.3\nServer Version: v1.13.10", "stdout_lines": ["Client Version: v1.13.3", "Server Version: v1.13.10"]}
...ignoring
TASK [team-services-pre-install-checks : debug] *************************************************************************************************************************
Thursday 05 December 2019 02:13:15 +0000 (0:00:00.902) 0:00:01.039 *****
ok: [localhost] => {
"k8s_version_live.stdout_lines": [
"Client Version: v1.13.3",
"Server Version: v1.13.10"
]
}```

Answer 1

As the error says:
conditional statements should not include jinja2 templating delimiters such as {{ }} or {% %}.
In a conditional statement, you are already inside a Jinja template context. You can just refer to variables by name:
- name: "Validate k8s version"
shell: "kubectl version --short"
register: k8s_version_live
failed_when: k8s_version_live.stdout_lines is not search(k8s_server_version)
ignore_errors: yes
Although you probably want k8s_version_live.stdout instead of k8s_version_live.stdout_lines.
I would probably write the task as:
- name: "Validate k8s version"
command: "kubectl version --short"
register: k8s_version_live
failed_when: k8s_server_version not in k8s_version_live.stdout
ignore_errors: true

Answer 2

Q: "Match a version ... match first two octets"
A: Use Version Comparison. For example, create the variable k8s_server_version from the registred output
- set_fact:
k8s_server_version: "{{ k8s_version_live.stdout_lines.1.split(':').1[2:] }}"
Compare the first two numbers of the version
- debug:
msg: "{{ k8s_server_version }} match 1.13"
when:
- k8s_server_version is version('1.13', '>=')
- k8s_server_version is version('1.14', '<')
gives
}
localhost | SUCCESS => {
"msg": "1.13.10 match 1.13"
}
Fail when the version does not match
- fail:
msg: "{{ k8s_server_version }} does not match 1.12"
when: not (k8s_server_version is version('1.12', '>=') and
k8s_server_version is version('1.13', '<'))
gives
localhost | FAILED! => {
"changed": false,
"msg": "1.13.10 does not match 1.12"
}