Use "requests" for CPU resources instead of limits

We now use a CPU request to ensure logging infrastructure pods are
not capped by default for CPU usage. It is still important to ensure
we have a minimum amount of CPU.

We keep the use of the variables *_cpu_limit so that the existing
behavior is maintained.

Note that we don't want to cap an infra pod's CPU usage by default,
since we want to be able to use the necessary resources to complete
it's tasks.

Bug 1501960 (https://bugzilla.redhat.com/show_bug.cgi?id=1501960)

3 files changed, 25 insertions, 6 deletions

diff --git a/roles/openshift_logging_fluentd/defaults/main.yml b/roles/openshift_logging_fluentd/defaults/main.yml
index 25f7580a4..861935c99 100644
--- a/roles/openshift_logging_fluentd/defaults/main.yml
+++ b/roles/openshift_logging_fluentd/defaults/main.yml
@@ -8,7 +8,8 @@ openshift_logging_fluentd_namespace: logging
 
 ### Common settings
 openshift_logging_fluentd_nodeselector: "{{ openshift_hosted_logging_fluentd_nodeselector_label | default('logging-infra-fluentd=true') | map_from_pairs }}"
-openshift_logging_fluentd_cpu_limit: 100m
+openshift_logging_fluentd_cpu_limit: null
+openshift_logging_fluentd_cpu_request: 100m
 openshift_logging_fluentd_memory_limit: 512Mi
 openshift_logging_fluentd_hosts: ['--all']
 
@@ -55,7 +56,7 @@ openshift_logging_fluentd_aggregating_passphrase: none
 #fluentd_throttle_contents:
 #fluentd_secureforward_contents:
 
-openshift_logging_fluentd_file_buffer_limit: 1Gi
+openshift_logging_fluentd_file_buffer_limit: 256Mi
 
 # Configure fluentd to tail audit log file and filter out container engine's logs from there
 # These logs are then stored in ES operation index
diff --git a/roles/openshift_logging_fluentd/tasks/main.yaml b/roles/openshift_logging_fluentd/tasks/main.yaml
index 06bb35dbc..f56810610 100644
--- a/roles/openshift_logging_fluentd/tasks/main.yaml
+++ b/roles/openshift_logging_fluentd/tasks/main.yaml
@@ -172,6 +172,9 @@
     ops_port: "{{ openshift_logging_fluentd_ops_port }}"
     fluentd_nodeselector_key: "{{ openshift_logging_fluentd_nodeselector.keys()[0] }}"
     fluentd_nodeselector_value: "{{ openshift_logging_fluentd_nodeselector.values()[0] }}"
+    fluentd_cpu_limit: "{{ openshift_logging_fluentd_cpu_limit }}"
+    fluentd_cpu_request: "{{ openshift_logging_fluentd_cpu_request }}"
+    fluentd_memory_limit: "{{ openshift_logging_fluentd_memory_limit }}"
     audit_container_engine: "{{ openshift_logging_fluentd_audit_container_engine | default(False) | bool }}"
     audit_log_file: "{{ openshift_logging_fluentd_audit_file | default() }}"
     audit_pos_log_file: "{{ openshift_logging_fluentd_audit_pos_file | default() }}"
diff --git a/roles/openshift_logging_fluentd/templates/fluentd.j2 b/roles/openshift_logging_fluentd/templates/fluentd.j2
index 644b70031..b07175a50 100644
--- a/roles/openshift_logging_fluentd/templates/fluentd.j2
+++ b/roles/openshift_logging_fluentd/templates/fluentd.j2
@@ -32,12 +32,27 @@ spec:
         imagePullPolicy: Always
         securityContext:
           privileged: true
+{% if (fluentd_memory_limit is defined and fluentd_memory_limit is not none) or (fluentd_cpu_limit is defined and fluentd_cpu_limit is not none) or (fluentd_cpu_request is defined and fluentd_cpu_request is not none) %}
         resources:
+{%   if (fluentd_memory_limit is defined and fluentd_memory_limit is not none) or (fluentd_cpu_limit is defined and fluentd_cpu_limit is not none) %}
           limits:
-            cpu: {{ openshift_logging_fluentd_cpu_limit }}
-            memory: {{ openshift_logging_fluentd_memory_limit }}
+{%     if fluentd_cpu_limit is not none %}
+            cpu: "{{fluentd_cpu_limit}}"
+{%     endif %}
+{%     if fluentd_memory_limit is not none %}
+            memory: "{{fluentd_memory_limit}}"
+{%     endif %}
+{%   endif %}
+{%   if (fluentd_memory_limit is defined and fluentd_memory_limit is not none) or (fluentd_cpu_request is defined and fluentd_cpu_request is not none) %}
           requests:
-            memory: {{ openshift_logging_fluentd_memory_limit }}
+{%     if fluentd_cpu_request is not none %}
+            cpu: "{{fluentd_cpu_request}}"
+{%     endif %}
+{%     if fluentd_memory_limit is not none %}
+            memory: "{{fluentd_memory_limit}}"
+{%     endif %}
+{%   endif %}
+{% endif %}
         volumeMounts:
         - name: runlogjournal
           mountPath: /run/log/journal
@@ -115,7 +130,7 @@ spec:
               containerName: "{{ daemonset_container_name }}"
               resource: limits.memory
         - name: "FILE_BUFFER_LIMIT"
-          value: "{{ openshift_logging_fluentd_file_buffer_limit | default('1Gi') }}"
+          value: "{{ openshift_logging_fluentd_file_buffer_limit | default('256i') }}"
 {% if openshift_logging_mux_client_mode is defined and
      ((openshift_logging_mux_allow_external is defined and openshift_logging_mux_allow_external | bool) or
       (openshift_logging_use_mux is defined and openshift_logging_use_mux | bool)) %}