From 33637b4ddf6b0561e740b9bf93f391b52f468605 Mon Sep 17 00:00:00 2001
From: Michele Baldessari <michele@acksyn.org>
Date: Thu, 3 Jun 2021 11:07:30 +0200
Subject: [PATCH] Add podman's events_logger option by default set to journald

By default podman 3.0.x sets the [engine]/events_logger to "file".
This causes every exec in podman to create a line of text in
/run/libpod/events/events.log like the following:

  {"ID":"412b6770c0b418e6d49a4801e71a198ddb81bbbefdaf1c9aad4d7948f77910ee","Image":"quay.io/centos/centos:latest","Name":"leak-test-7","Status":"exec","Time":"2021-06-03T08:36:05.237964012Z","Type":"container","Attributes":{"org.label-schema.build-date":"20201204","org.label-schema.license":"GPLv2","org.label-schema.name":"CentOS Base Image","org.label-schema.schema-version":"1.0","org.label-schema.vendor":"CentOS"}}

Since by default /run is mounted on tmpfs, this has the side-effect of
increasing kernel slab objects over time indefinitely eventually causing
an OOM of the box.

We initially wanted to switch to the 'none' backend, but the podman
folks recommended using the journald backend because events logs are
used by podman in case of a rare race when running "podman run --rm".
Given that we call run with --rm from in a multithreaded fashion this
seems to be the safest approach. The drawback of using journald is
that events won't be logged for rootless containers unless the user
is part of the 'wheel' group. We believe we're not using those
containers in tripleo anyways, so this should be safe.

Tested by applying a backport of this patch to Train + podman 3.0.x and
got the following:
[root@controller-0 containers]# ls -la /run/libpod/events/
total 0
drwx------. 2 root root  40 Jun  3 11:55 .
drwxr-x--x. 5 root root 140 Jun  3 11:55 ..

[root@controller-0 containers]# more /etc/containers/containers.conf
[containers]
pids_limit = 4096
[engine]
events_logger = "journald"

Also tested the override via the corresponding THT change in
Ieffe2852111c3ec8347343a042dd78bbf691d79a.

Closes-Bug: #1923607

Change-Id: I780103e17f1bb42a0546c30bd6c001c642ad88b3
(cherry picked from commit f31bab878bfd3332c20a10bf9ca26d443028d214)
(cherry picked from commit 79be78bba35199c5b26632e51d8bda411a8239c5)
(cherry picked from commit 637db1c401c6c6a0d2e3cef26ab8a97cc3b31bf2)
---
 .../roles/tripleo_podman/defaults/main.yml          |  1 +
 .../tripleo_podman/tasks/tripleo_podman_install.yml | 13 ++++++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/tripleo_ansible/roles/tripleo_podman/defaults/main.yml b/tripleo_ansible/roles/tripleo_podman/defaults/main.yml
index 07453db36..ca109131b 100644
--- a/tripleo_ansible/roles/tripleo_podman/defaults/main.yml
+++ b/tripleo_ansible/roles/tripleo_podman/defaults/main.yml
@@ -77,3 +77,4 @@ tripleo_podman_default_network_config:
 #     blocked: true
 tripleo_podman_registries: []
 tripleo_container_default_pids_limit: 4096
+tripleo_container_events_logger_mechanism: journald
diff --git a/tripleo_ansible/roles/tripleo_podman/tasks/tripleo_podman_install.yml b/tripleo_ansible/roles/tripleo_podman/tasks/tripleo_podman_install.yml
index edad07510..367fd1179 100644
--- a/tripleo_ansible/roles/tripleo_podman/tasks/tripleo_podman_install.yml
+++ b/tripleo_ansible/roles/tripleo_podman/tasks/tripleo_podman_install.yml
@@ -70,6 +70,13 @@
         setype: etc_t
         mode: '0644'
         create: true
-        section: containers
-        option: pids_limit
-        value: "{{ tripleo_container_default_pids_limit }}"
+        section: "{{ item.section }}"
+        option: "{{ item.option }}"
+        value: "{{ item.value }}"
+      loop:
+        - section: containers
+          option: pids_limit
+          value: "{{ tripleo_container_default_pids_limit }}"
+        - section: engine
+          option: events_logger
+          value: "\"{{ tripleo_container_events_logger_mechanism }}\""