syncset.md

SyncSet

Overview

SyncSet and SelectorSyncSet objects facilitate resource management (create, update, delete, patch) in hive-managed clusters.

To use SyncSet objects to manage resources, you must create them in the same namespace as the ClusterDeployment resource that they manage. If you want to manage resources in clusters that match a specific label use SelectorSyncSet instead. These objects apply changes to clusters in any namespace that match the clusterDeploymentSelector that you set.

With both SyncSets and SelectorSyncSets, the individual resources and patches are reapplied when 2 hours have passed since their last reconciliation or if their contents are updated in the SyncSet or SelectorSyncSets.

SyncSet Object Definition

SyncSets may contain a list of resource object definitions to create and a list of patches to be applied to existing objects.

---
apiVersion: hive.openshift.io/v1alpha1
kind: SyncSet
metadata:
  name: mygroup
spec:
  clusterDeploymentRefs:
  - name: ClusterName

  resourceApplyMode: Upsert

  resources:
  - apiVersion: user.openshift.io/v1
    kind: Group
    metadata:
      name: mygroup
    users:
    - myuser

  patches:
  - kind: ConfigMap
    apiVersion: v1
    name: foo
    namespace: default
    applyMode: AlwaysApply
    patch: |-
      { "data": { "foo": "new-bar" } }
    patchType: merge

Field	Usage
clusterDeploymentRefs	List of ClusterDeployment names in the current namespace which the SyncSet will apply to.
resourceApplyMode	Defaults to "Upsert", which indicates that objects will be created and updated to match the SyncSet. Existing resources that are not listed in the SyncSet are retained. Specify "Sync" to delete existing objects that were previously in the resources list.
resources	A list of resource object definitions. Resources will be created in the referenced clusters.
patches	A list of patches to apply to existing resources in the referenced clusters. You can include any valid cluster object type in the list. By default, the patch applyMode value is "AlwaysApply", which applies the patch every 2 hours. You can also specify"ApplyOnce" to apply the patch only once.

Example of SyncSet use

In this example you can change the replicaset of a deployment running on top of a Hive managed OpenShift cluster.

• Get the required information of the deployment

$ oc get deployment <deployment name> -o yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app: sise
  name: sise-deploy
  namespace: default
  replicas: 2
  xxxxxxx

• Create the SyncSet object in the cluster deployment namespace in Hive managed cluster as mentioned below.

oc create -f <syncset_file.yaml> -n <namespace>

SyncSet File:

apiVersion: hive.openshift.io/v1alpha1
kind: SyncSet
metadata:
  name: sise-deploy-syncset
spec:
  clusterDeploymentRefs:
  - name: <cluster name>

  patches:
  - kind: Deployment
    apiVersion: extensions/v1beta1
    name: sise-deploy
    namespace: default
    patch: |-
      { "spec": { "replicas": 3 } }
    patchType: strategic

• To see the syncset status, run as below.

oc get syncsetinstances <synsetinstance name> -o yaml

SelectorSyncSet Object Definition

SelectorSyncSet functions identically to SyncSet but is applied to clusters matching clusterDeploymentSelector in any namespace.

---
apiVersion: hive.openshift.io/v1alpha1
kind: SelectorSyncSet
metadata:
  name: mygroup
spec:
  resources:
  - apiVersion: user.openshift.io/v1
    kind: Group
    metadata:
      name: mygroup
    users:
    - abutcher
  clusterDeploymentSelector:
    matchLabels:
      cluster-group: abutcher

Field	Usage
clusterDeploymentSelector	A key/value label pair which selects matching ClusterDeployments in any namespace.

Diagnosing SyncSet Failures

The failure logs for syncset is present in Hive controller POD logs.

To find the status of the syncset, check the corresponding syncsetinstance object in the cluster deployment namespace.

oc get syncsetinstance -n <namespace>

To see details, run as below.

oc get syncsetinstances <synsetinstance name> -o yaml