[Feature] Maintenance Mode (#516)

Author: ajanikow

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Change Log
 
+## Master
+- Add Maintenance mode annotation for ArangoDeployment
+
 ## [0.4.2](https://github.com/arangodb/kube-arangodb/tree/0.4.2) (2019-11-12)
 - AntiAffinity for operator pods.
 - Add CRD API v1 with support for v1alpha.

docs/design/README.md

@@ -8,3 +8,4 @@
 - [Scaling](./scaling.md)
 - [Status](./status.md)
 - [Upgrading](./upgrading.md)
+- [Maintenance](./maintenance.md)

docs/design/maintenance.md

@@ -0,0 +1,14 @@
+# Maintenance
+
+## ArangoDeployment
+
+Maintenance on ArangoDeployment can be enabled using annotation.
+
+Key: `deployment.arangodb.com/maintenance`
+Value: `true`
+
+To enable maintenance mode for ArangoDeployment kubectl command can be used:
+`kubectl annotate arangodeployment deployment deployment.arangodb.com/maintenance=true`
+
+To disable maintenance mode for ArangoDeployment kubectl command can be used:
+`kubectl annotate --overwrite arangodeployment deployment deployment.arangodb.com/maintenance-`

go.mod

@@ -55,7 +55,7 @@ require (
 	github.com/helm/helm v2.14.3+incompatible // indirect
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect
 	github.com/jessevdk/go-assets v0.0.0-20160921144138-4f4301a06e15
-	github.com/jessevdk/go-assets-builder v0.0.0-20130903091706-b8483521738f // indirect
+	github.com/jessevdk/go-assets-builder v0.0.0-20130903091706-b8483521738f
 	github.com/jessevdk/go-flags v1.4.0 // indirect
 	github.com/jonboulle/clockwork v0.1.0 // indirect
 	github.com/juju/errgo v0.0.0-20140925100237-08cceb5d0b53 // indirect

pkg/deployment/deployment_inspector.go

@@ -37,6 +37,10 @@ var (
 	inspectDeploymentDurationGauges = metrics.MustRegisterGaugeVec(metricsComponent, "inspect_deployment_duration", "Amount of time taken by a single inspection of a deployment (in sec)", metrics.DeploymentName)
 )
 
+const (
+	arangoDeploymentMaintenanceAnnotation = "deployment.arangodb.com/maintenance"
+)
+
 // inspectDeployment inspects the entire deployment, creates
 // a plan to update if needed and inspects underlying resources.
 // This function should be called when:
@@ -68,6 +72,14 @@ func (d *Deployment) inspectDeployment(lastInterval util.Interval) util.Interval
 			d.CreateEvent(k8sutil.NewErrorEvent("ArangoDeployment finalizer inspection failed", err, d.apiObject))
 		}
 	} else {
+		// Check if maintenance annotation is set
+		if updated != nil && updated.Annotations != nil {
+			if v, ok := updated.Annotations[arangoDeploymentMaintenanceAnnotation]; ok && v == "true" {
+				// Disable checks if we will enter maintenance mode
+				log.Info().Str("deployment", deploymentName).Msg("Deployment in maintenance mode")
+				return nextInterval
+			}
+		}
 		// Is the deployment in failed state, if so, give up.
 		if d.GetPhase() == api.DeploymentPhaseFailed {
 			log.Debug().Msg("Deployment is in Failed state.")

tools/tools.go

@@ -0,0 +1,23 @@
+//
+// DISCLAIMER
+//
+// Copyright 2020 ArangoDB GmbH, Cologne, Germany
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+
+package tools
+
+import _ "github.com/jessevdk/go-assets-builder"