Initial support for RHEL8

[cp-elastic]

This PR fixes RHEL8's configurations to work with the new Podman workflow.

Related:
#196
#182

[smalenfant]

This is not only for RHEL8, but please see that specific diff for systemd (podman-restart.service) that's required when a server reboots to restart the ECE services. I also added the "docker" command specific by the documentation (optional).

 - name: Podman daemon is enabled and systemd has read all changes
-  systemd:
+  ansible.builtin.systemd:
     name: "{{ item }}"
     enabled: yes
     daemon_reload: yes
   loop:
     - podman.service
-    - podman.socket
\ No newline at end of file
+    - podman.socket
+    - podman-restart.service
+
+- name: Create docker cmd redirect to podman
+  ansible.builtin.copy:
+    content: |
+      #!/bin/bash
+      podman-remote --url unix:///var/run/podman/podman.sock "$@"
+    dest: /usr/bin/docker
+    mode: 0755
\ No newline at end of file

[cp-elastic]

@smalenfant Good catch on podman-restart.service, I will add that. I'm not sure I follow what the purpose of the copy task is for. The podman-docker package does something similar, but I chose to omit it to reduce complexity.

[smalenfant]

@smalenfant Good catch on podman-restart.service, I will add that. I'm not sure I follow what the purpose of the copy task is for. The podman-docker package does something similar, but I chose to omit it to reduce complexity.

I don't think we need that fake docker to podman link. This was only something documented by Elastic. Maybe required for diagnostics? I don't know.

RHEL/Rocky Step 14

[fgierlinger]

@cp-elastic I noticed on a recent execution of the playbook, that there is another task in tasks/vmimage/main.yml that fails when podman is used as container engine.

ansible-elastic-cloud-enterprise/tasks/vmimage/main.yml

Lines 2 to 6 in c7ddbc3

	- name: stop and disable docker
	systemd:
	name: docker
	state: stopped
	enabled: no

I managed to fix it, by adding the conditional when: container_engine == "Docker"

[cp-elastic]

@fgierlinger That's odd, I didn't run into that in testing. It does seem like that simple fix should suffice. Thank you!