elasticsearch-operator

WORK IN PROGRESS

Elasticsearch operator to run Elasticsearch cluster on top of Openshift and Kubernetes. Operator uses Operator Framework SDK.

Why use operator?

Operator is designed to provide self-service for the Elasticsearch cluster operations. See the diagram on operator maturity model.

• Elasticsearch operator ensures proper layout of the pods
• Elasticsearch operator enables proper rolling cluster restarts
• Elasticsearch operator provides kubectl interface to manage your Elasticsearch cluster
• Elasticsearch operator provides kubectl interface to monitor your Elasticsearch cluster

Getting started

Prerequisites

• Cluster administrator must set vm.max_map_count sysctl to 262144 on the host level of each node in your cluster prior to running the operator.
• In case hostmounted volume is used, the directory on the host must have 777 permissions and the following selinux labels (TODO).
• In case secure cluster is used the certificates must be pre-generated and uploaded to the secret <elasticsearch_cluster_name>-certs

Kubernetes

Make sure certificates are pre-generated and deployed as secret. Upload the Custom Resource Definition to your Kubernetes cluster:

$ kubectl create -f deploy/crd.yaml

Deploy the required roles to the cluster:

$ kubectl create -f deploy/rbac.yaml

Deploy custom resource and the Deployment resource of the operator:

$ kubectl create -f deploy/cr.yaml
$ kubectl create -f deploy/operator.yaml

OpenShift

As a cluster admin apply the template with the roles and permissions:

$ oc process -f deploy/openshift/admin-elasticsearch-template.yaml | oc apply -f -

The template deploys CRD, roles and rolebindings. You can pass variables:

• NAMESPACE to specify which namespace's default ServiceAccount will be allowed to manage the Custom Resource.
• ELASTICSEARCH_ADMIN_USER to specify which user of OpenShift will be allowed to manage the Custom Resource.

For example:

$ oc process NAMESPACE=myproject ELASTICSEARCH_ADMIN_USER=developer -f deploy/openshift/admin-elasticsearch-template.yaml | oc apply -f -

In case later-on grant permissions to extra users by giving them the role elasticsearch-operator.

As the user which was specified as ELASTICSEARCH_ADMIN_USER on previous step:

Make sure the secret with Elasticsearch certificates exists and is named <elasticsearch_cluster_name>-certs

Then process the following template:

$ oc process -f deploy/openshift/elasticsearch-template.yaml | oc apply -f -

The template deploys the Custom Resource and the operator deployment. You can pass the following variables to the template:

• NAMESPACE - namespace where the Elasticsearch cluster will be deployed. Must be the same as the one specified by admin
• ELASTICSEARCH_CLUSTER_NAME - name of the Elasticsearch cluster to be deployed

For example:

$ oc process NAMESPACE=myproject ELASTICSEARCH_CLUSTER_NAME=elastic1 -f deploy/openshift/elasticsearch-template.yaml | oc apply -f -

Customize your cluster

Image customization

The operator is designed to work with openshift/origin-aggregated-logging image.

Storage configuration

Storage is configurable per individual node type. Possible configuration options:

• Hostmounted directory
• Empty directory
• Existing PersistentVolume
• New PersistentVolume generated by StorageClass

Elasticsearch cluster topology customization

Decide how many nodes you want to run.

Elasticsearch node configuration customization

TODO

Supported features

Kubernetes TBD+ and OpenShift TBD+ are supported.

• SSL-secured deployment (using Searchguard)
• Insecure deployment (requires different image)
• Index per tenant
• Logging to a file or to console
• Elasticsearch 6.x support
• Elasticsearch 5.6.x support
• Master role
• Client role
• Data role
• Clientdata role
• Clientdatamaster role
• Elasticsearch snapshots
• Prometheus monitoring
• Status monitoring
• Rolling restarts