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The KubeDB operator allows a user to deploy an Elasticsearch cluster with custom configuration files. The operator also allows the user to configure the security plugins such as X-Pack, SearchGurad, and OpenDistro. If the custom configuration files are not provided, the operator will start the cluster with default configurations.
Elasticsearch has three configuration files:
elasticsearch.yml: for configuring Elasticsearch
jvm.options: for configuring Elasticsearch JVM settings
log4j2.properties: for configuring Elasticsearch logging
In KubeDB managed Elasticsearch cluster, the configuration files are located at
/usr/share/elasticsearch/config directory of Elasticsearch pods. To know more about configuring the Elasticsearch cluster see here.
X-Pack security plugin has the following configuration files:
roles.yml- define roles and the associated permissions.
role_mapping.yml- define which roles should be assigned to each user based on their username, groups, or other metadata.
SearchGuard security plugin has the following configuration files:
sg_config.yml- configure authenticators and authorization backends.
sg_roles.yml- define roles and the associated permissions.
sg_roles_mapping.yml- map backend roles, hosts, and users to roles.
sg_internal_users.yml- stores users, and hashed passwords in the internal user database.
sg_action_groups.yml- define named permission groups.
sg_tenants.yml- defines tenants for configuring the Kibana access.
sg_blocks.yml- defines blocked users and IP addresses.
OpenDistro security plugin has the following configuration files:
internal_users.yml- contains any initial users that you want to add to the security plugin’s internal user database.
roles.yml- contains any initial roles that you want to add to the security plugin.
roles_mapping.yml- maps backend roles, hosts, and users to roles.
action_groups.yml- contains any initial action groups that you want to add to the security plugin.
tenants.yml- contains the tenant configurations.
nodes_dn.yml- contains nodesDN mapping name and corresponding values.
The custom configuration files are passed via a Kubernetes secret. The file names are the keys of the Secret with the file-contents as the values. The secret name needs to be mentioned in
spec.configSecret.name of the Elasticsearch object.
apiVersion: kubedb.com/v1alpha2 kind: Elasticsearch metadata: name: es-custom-config namespace: demo spec: version: searchguard-7.9.3 configSecret: name: es-custom-config
apiVersion: v1 kind: Secret metadata: name: es-custom-config namespace: demo stringData: elasticsearch.yml: |- logger.org.elasticsearch.discovery: DEBUG
How the resultant configuration files are generated?
YML: The default configuration file pre-stored at config directories is overwritten by the operator-generated configuration file (if any). Then the resultant configuration file is overwritten by the user-provided custom configuration file (if any). The yq tool is used to merge two YAML files.
$ yq merge -i --overwrite file1.yml file2.yml
Non-YML: The default configuration file is replaced by the operator-generated one (if any). Then the resultant configuration file is replaced by the user-provided custom configuration file (if any).
$ cp -f file2 file1
How to provide node-role specific configurations?
If an Elasticsearch cluster is running in the topology mode (ie.
spec.topology is set), a user may want to provide node-role specific configurations, say configurations that will only be merged to
master nodes. To achieve this, users need to add the node role as a prefix to the file name.
data-elasticsearch.yml: Only applied to
master-jvm.options: Only applied to
ingest-log4j2.properties: Only applied to
elasticsearch.yml: applied to all nodes.
How to provide additional files that are referenced from the configurations?
All these files provided via
configSecret is stored in each Elasticsearch node (i.e. pod) at
ES_CONFIG_DIR/custom_config/ ( i.e.
/usr/share/elasticsearch/config/custom_config/) directory. So, user can use this path while configuring the Elasticsearch.