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_node_selector`: Selector for the nodes prometheus will be deployed on.

- `openshift_prometheus_<COMPONENT>_image_prefix`: specify image prefix for the component 

- `openshift_prometheus_<COMPONENT>_image_version`: specify image version for the component 

- `openshift_prometheus_args`: Modify or add arguments for prometheus application

- `openshift_prometheus_hostname`: specify the hostname for the route to prometheus `prometheus-{{openshift_prometheus_namespace}}.{{openshift_master_default_subdomain}}`

- `openshift_prometheus_alerts_hostname`: specify the hostname for the route to prometheus-alerts `prometheus_alerts-{{openshift_prometheus_namespace}}.{{openshift_master_default_subdomain}}`

e.g
```
openshift_prometheus_args=['--storage.tsdb.retention=6h', '--storage.tsdb.min-block-duration=5s', '--storage.tsdb.max-block-duration=6m']
```

## PVC related variables
Each prometheus component (prometheus, alertmanager, alertbuffer) can set pv claim by setting corresponding role variable:
```
openshift_prometheus_<COMPONENT>_storage_type: <VALUE> (pvc, emptydir)
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]
```

## NFS PV Storage variables
Each prometheus component (prometheus, alertmanager, alertbuffer) can set nfs pv by setting corresponding variable:
```
openshift_prometheus_<COMPONENT>_storage_kind=<VALUE>
openshift_prometheus_<COMPONENT>_storage_(access_modes|host|labels)=<VALUE>
openshift_prometheus_<COMPONENT>_storage_volume_(name|size)=<VALUE>
openshift_prometheus_<COMPONENT>_storage_nfs_(directory|options)=<VALUE>
```
e.g
```
openshift_prometheus_storage_kind=nfs
openshift_prometheus_storage_access_modes=['ReadWriteOnce']
openshift_prometheus_storage_host=nfs.example.com #for external host
openshift_prometheus_storage_nfs_directory=/exports
openshift_prometheus_storage_alertmanager_nfs_options='*(rw,root_squash)'
openshift_prometheus_storage_volume_name=prometheus
openshift_prometheus_storage_alertbuffer_volume_size=10Gi
openshift_prometheus_storage_labels={'storage': 'prometheus'}
```

NOTE: Setting `openshift_prometheus_<COMPONENT>_storage_labels` overrides `openshift_prometheus_<COMPONENT>_pvc_pv_selector`


## 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