Create ansible role for deploying prometheus on openshift

A new role for installing prometheus on openshift.
Depends on `openshift_hosted_prometheus_deploy` flag

role creates:
- prometheus namespace
- prometheus clusterrolebinding and service account
- pvs for prometheus, alertmanager and alertbuffer for internal nfs
- prometheus pod with prometheus behind oauth-proxy, alertmanager and alert-buffer behind oauth-proxy
- prometheus and alertmanager configmaps
- prometheus and alerts services and direct routes
- prometheus, alertmanager and alert-buffer pvcs

1 files changed, 95 insertions, 0 deletions

diff --git a/roles/openshift_prometheus/README.md b/roles/openshift_prometheus/README.md
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+OpenShift Prometheus
+====================
+
+OpenShift Prometheus Installation
+
+Requirements
+------------
+
+
+Role Variables
+--------------
+
+For default values, see [`defaults/main.yaml`](defaults/main.yaml).
+
+- `openshift_prometheus_state`: present - install/update. absent - uninstall.
+
+- `openshift_prometheus_namespace`: project (i.e. namespace) where the components will be
+  deployed.
+
+- `openshift_prometheus_replicas`: The number of replicas for prometheus deployment.
+
+- `openshift_prometheus_node_selector`: Selector for the nodes prometheus will be deployed on.
+
+- `openshift_prometheus_image_<COMPONENT>`: specify image for the component 
+
+## Storage related variables
+Each prometheus component (prometheus, alertmanager, alert-buffer, oauth-proxy) can set pv claim by setting corresponding role variable:
+```
+openshift_prometheus_<COMPONENT>_storage_type: <VALUE>
+openshift_prometheus_<COMPONENT>_pvc_(name|size|access_modes|pv_selector): <VALUE>
+```
+e.g
+```
+openshift_prometheus_storage_type: pvc
+openshift_prometheus_alertmanager_pvc_name: alertmanager
+openshift_prometheus_alertbuffer_pvc_size: 10G
+openshift_prometheus_pvc_access_modes: [ReadWriteOnce]
+```
+
+## Additional Alert Rules file variable
+An external file with alert rules can be added by setting path to additional rules variable: 
+```
+openshift_prometheus_additional_rules_file: <PATH> 
+```
+
+File content should be in prometheus alert rules format.
+Following example sets rule to fire an alert when one of the cluster nodes is down:
+
+```
+groups:
+- name: example-rules
+  interval: 30s # defaults to global interval
+  rules:
+  - alert: Node Down
+    expr: up{job="kubernetes-nodes"} == 0
+    annotations:
+      miqTarget: "ContainerNode"
+      severity: "HIGH"
+      message: "{{ '{{' }}{{ '$labels.instance' }}{{ '}}' }} is down"
+```
+
+
+## Additional variables to control resource limits
+Each prometheus component (prometheus, alertmanager, alert-buffer, oauth-proxy) can specify a cpu and memory limits and requests by setting
+the corresponding role variable:
+```
+openshift_prometheus_<COMPONENT>_(limits|requests)_(memory|cpu): <VALUE>
+```
+e.g
+```
+openshift_prometheus_alertmanager_limits_memory: 1Gi
+openshift_prometheus_oath_proxy_requests_cpu: 100
+```
+
+Dependencies
+------------
+
+openshift_facts
+
+
+Example Playbook
+----------------
+
+```
+- name: Configure openshift-prometheus
+  hosts: oo_first_master
+  roles:
+  - role: openshift_prometheus
+```
+
+License
+-------
+
+Apache License, Version 2.0
+