Skip to content

Latest commit

 

History

History
256 lines (196 loc) · 10.9 KB

cluster_manifest.md

File metadata and controls

256 lines (196 loc) · 10.9 KB
Raw

Individual postgres clusters are described by the Kubernetes cluster manifest that has the structure defined by the postgres CRD (custom resource definition). The following section describes the structure of the manifest and the purpose of individual keys. You can take a look at the examples of the minimal and the complete cluster manifests.

When Kubernetes resources, such as memory, CPU or volumes, are configured, their amount is usually described as a string together with the units of measurements. Please, refer to the Kubernetes documentation for the possible values of those.

Manifest structure

A postgres manifest is a YAML document. On the top level both individual parameters and parameter groups can be defined. Parameter names are written in camelCase.

Cluster metadata

Those parameters are grouped under the metadata top-level key.

  • name the name of the cluster. Must start with the teamId followed by a dash. Changing it after the cluster creation is not supported. Required field.

  • namespace the namespace where the operator creates Kubernetes objects (i.e. pods, services, secrets) for the cluster. Changing it after the cluster creation results in deploying or updating a completely separate cluster in the target namespace. Optional (if present, should match the namespace where the manifest is applied).

Top-level parameters

Those are parameters grouped directly under the spec key in the manifest.

  • teamId name of the team the cluster belongs to. Changing it after the cluster creation is not supported. Required field.

  • dockerImage custom docker image that overrides the docker_image operator parameter. It should be a Spilo image. Optional.

  • enableMasterLoadBalancer boolean flag to override the operator defaults (set by the enable_master_load_balancer parameter) to define whether to enable the load balancer pointing to the postgres primary. Optional.

  • enableReplicaLoadBalancer boolean flag to override the operator defaults (set by the enable_replica_load_balancer parameter) to define whether to enable the load balancer pointing to the postgres standby instances. Optional.

  • allowedSourceRanges when one or more load balancers are enabled for the cluster, this parameter defines the comma-separated range of IP networks (in CIDR-notation). The corresponding load balancer is accessible only to the networks defined by this parameter. Optional, when empty the load balancer service becomes inaccessible from outside of the Kubernetes cluster.

  • numberOfInstances total number of instances for a given cluster. The operator parameters max_instances and min_instances may also adjust this number. Required field.

  • users a map of usernames to user flags for the users that should be created in the cluster by the operator. User flags are a list, allowed elements are SUPERUSER, REPLICATION, INHERIT, LOGIN, NOLOGIN, CREATEROLE, CREATEDB, BYPASSURL. A login user is created by default unless NOLOGIN is specified, in which case the operator creates a role. One can specify empty flags by providing a JSON empty array '[]'. Optional.

  • databases a map of database names to database owners for the databases that should be created by the operator. The owner users should already exist on the cluster (i.e. mentioned in the user parameter). Optional.

  • tolerations a list of tolerations that apply to the cluster pods. Each element of that list is a dictionary with the following fields: key, operator, value, effect and tolerationSeconds. Each field is optional. See Kubernetes examples for details on tolerations and possible values of those keys. When set, this value overrides the pod_toleration setting from the operator. Optional.

  • podPriorityClassName a name of the priority class that should be assigned to the cluster pods. When not specified, the value is taken from the pod_priority_class_name operator parameter, if not set then the default priority class is taken. The priority class itself must be defined in advance.

  • enableShmVolume Start a database pod without limitations on shm memory. By default docker limit /dev/shm to 64M (see e.g. the docker issue, which could be not enough if PostgreSQL uses parallel workers heavily. If this option is present and value is true, to the target database pod will be mounted a new tmpfs volume to remove this limitation. If it's not present, the decision about mounting a volume will be made based on operator configuration (enable_shm_volume, which is true by default). It it's present and value is false, then no volume will be mounted no matter how operator was configured (so you can override the operator configuration).

Postgres parameters

Those parameters are grouped under the postgresql top-level key.

  • version the postgres major version of the cluster. Looks at the Spilo project for the list of supported versions. Changing the cluster version once the cluster has been bootstrapped is not supported. Required field.

  • parameters a dictionary of postgres parameter names and values to apply to the resulting cluster. Optional (Spilo automatically sets reasonable defaults for parameters like work_mem or max_connections).

Patroni parameters

Those parameters are grouped under the patroni top-level key. See the patroni documentation for the explanation of ttl and loop_wait parameters.

  • initdb a map of key-value pairs describing initdb parameters. For data-checksum, debug, no-locale, noclean, nosync and sync-only parameters use true as the value if you want to set them. Changes to this option do not affect the already initialized clusters. Optional.

  • pg_hba list of custom pg_hba lines to replace default ones. Note that the default ones include

    hostsll all +pamrole all pam

    , where pamrole is the name of the role for the pam authentication; any custom pg_hba should include the pam line to avoid breaking pam authentication. Optional.

  • ttl patroni ttl parameter value, optional. The default is set by the Spilo docker image. Optional.

  • loop_wait patroni loop_wait parameter value, optional. The default is set by the Spilo docker image. Optional.

  • retry_timeout patroni retry_timeout parameter value, optional. The default is set by the Spilo docker image. Optional.

  • maximum_lag_on_failover patroni maximum_lag_on_failover parameter value, optional. The default is set by the Spilo docker image. Optional.

  • slots permanent replication slots that Patroni preserves after failover by re-creating them on the new primary immediately after doing a promote. Slots could be reconfigured with the help of patronictl edit-config. It is the responsibility of a user to avoid clashes in names between replication slots automatically created by Patroni for cluster members and permanent replication slots. Optional.

Postgres container resources

Those parameters define CPU and memory requests and limits for the postgres container. They are grouped under the resources top-level key. There are two subgroups, requests and limits.

Requests

CPU and memory requests for the postgres container.

  • cpu CPU requests for the postgres container. Optional, overrides the default_cpu_requests operator configuration parameter. Optional.

  • memory memory requests for the postgres container. Optional, overrides the default_memory_request operator configuration parameter. Optional.

Limits

CPU and memory limits for the postgres container.

  • cpu CPU limits for the postgres container. Optional, overrides the default_cpu_limits operator configuration parameter. Optional.

  • memory memory limits for the postgres container. Optional, overrides the default_memory_limits operator configuration parameter. Optional.

Parameters defining how to clone the cluster from another one

Those parameters are applied when the cluster should be a clone of another one that is either already running or has a basebackup on S3. They are grouped under the clone top-level key and do not affect the already running cluster.

  • cluster name of the cluster to clone from. Translated to either the service name or the key inside the S3 bucket containing base backups. Required when the clone section is present.

  • uid Kubernetes UID of the cluster to clone from. Since cluster name is not a unique identifier of the cluster (as identically named clusters may exist in different namespaces) , the operator uses UID in the S3 bucket name in order to guarantee uniqueness. Has no effect when cloning from the running clusters. Optional.

  • timestamp the timestamp up to which the recovery should proceed. The operator always configures non-inclusive recovery target, stopping right before the given timestamp. When this parameter is set the operator will not consider cloning from the live cluster, even if it is running, and instead goes to S3. Optional.

EBS volume resizing

Those parameters are grouped under the volume top-level key and define the properties of the persistent storage that stores postgres data.

  • size the size of the target EBS volume. Usual Kubernetes size modifiers, i.e. Gi or Mi, apply. Required.

  • storageClass the name of the Kubernetes storage class to draw the persistent volume from. See Kubernetes documentation for the details on storage classes. Optional.

Sidecar definitions

Those parameters are defined under the sidecars key. They consist of a list of dictionaries, each defining one sidecar (an extra container running along the main postgres container on the same pod). The following keys can be defined in the sidecar dictionary: