csantanapr closed pull request #215: Document persistent volumes and use of
external db
URL: https://github.com/apache/incubator-openwhisk-deploy-kube/pull/215
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diff --git a/docs/configurationChoices.md b/docs/configurationChoices.md
index e62bc38..4545228 100644
--- a/docs/configurationChoices.md
+++ b/docs/configurationChoices.md
@@ -36,6 +36,53 @@ controller:
replicaCount: 2
```
+### Using an external database
+
+You may want to use an external CouchDB or Cloudant instance instead
+of deploying a CouchDB instance as a Kubernetes pod. You can do this
+by adding a stanza like the one below to your `mycluster.yaml`,
+substituting in the appropriate values for `<...>`
+```yaml
+db:
+ external: true
+ host: <db hostname or ip addr>
+ port: <db port>
+ protocol: <"http" or "https">
+ auth:
+ username: <username>
+ password: <password>
+```
+
+Note that if you use an external database, the Helm deployment process
+will not attempt to create the necessary database tables or otherwise
+initialize/wipe the database. You will need to properly initialize
+your external database before deploying the OpenWhisk chart.
+
+### Persistence
+
+The couchdb, zookeeper, kafka, and redis microservices can each be
+configured to use persistent volumes to store their data. Enabling
+persistence may allow the system to survive failures/restarts of these
+components without a complete loss of application state. By default,
+none of these services is configured to use persistent volumes. To
+enable persistence, you can add stanzas like the following to your
+`mycluster.yaml` to enable persistence and to request an appropriately
+sized volume.
+
+```yaml
+redis:
+ persistence:
+ enabled: true
+ size: 256Mi
+ storageClass: default
+```
+If you are deploying on a managed Kubernetes cluster, check the cloud
+provider's documentation to determine the appropriate `storageClass`
+and `size` to request.
+
+*Limitation* Currently the persistent volume support assumes that the
+`replicaCount` of the deployment using the persistent volume is 1.
+
### Invoker Container Factory
The Invoker is responsible for creating and managing the containers
diff --git a/helm/templates/_helpers.tpl b/helm/templates/_helpers.tpl
index c386a31..3bd6c7d 100644
--- a/helm/templates/_helpers.tpl
+++ b/helm/templates/_helpers.tpl
@@ -13,8 +13,12 @@
{{/* hostname for database */}}
{{- define "db_host" -}}
+{{- if .Values.db.external -}}
+{{ .Values.db.host }}
+{{- else -}}
{{ .Values.db.name }}.{{ .Release.Namespace }}.svc.cluster.local
{{- end -}}
+{{- end -}}
{{/* hostname for kafka */}}
{{- define "kafka_host" -}}
diff --git a/helm/templates/_readiness.tpl b/helm/templates/_readiness.tpl
index 8e53ec0..fea7a24 100644
--- a/helm/templates/_readiness.tpl
+++ b/helm/templates/_readiness.tpl
@@ -3,6 +3,9 @@
{{/* Init container that waits for couchdb to be ready */}}
{{- define "readiness.waitForCouchDB" -}}
+{{ if .Values.db.external }}
+# external db is assumed to be already ready; no need for init container
+{{- else -}}
- name: "wait-for-couchdb"
image: "busybox"
imagePullPolicy: "IfNotPresent"
@@ -11,6 +14,7 @@
value: {{ .Values.db.protocol }}://{{ include "db_host" . }}:{{
.Values.db.port }}/{{ .Values.db.activationsTable }}
command: ["sh", "-c", "result=1; until [ $result -eq 0 ]; do echo verifying
CouchDB readiness; wget -T 5 --spider $READINESS_URL; result=$?; sleep 1;
done;"]
{{- end -}}
+{{- end -}}
{{/* Init container that waits for kafka to be ready */}}
{{- define "readiness.waitForKafka" -}}
diff --git a/helm/templates/couchdb.yaml b/helm/templates/couchdb.yaml
index 1c7f16b..edd9529 100644
--- a/helm/templates/couchdb.yaml
+++ b/helm/templates/couchdb.yaml
@@ -1,6 +1,7 @@
# Licensed to the Apache Software Foundation (ASF) under one or more
contributor
# license agreements; and to You under the Apache License, Version 2.0.
+{{ if not .Values.db.external }}
apiVersion: v1
kind: Service
metadata:
@@ -100,3 +101,5 @@ spec:
requests:
storage: {{ .Values.db.persistence.size }}
{{- end }}
+
+{{ end }}
diff --git a/helm/values.yaml b/helm/values.yaml
index 4e2c19f..ff20a08 100644
--- a/helm/values.yaml
+++ b/helm/values.yaml
@@ -1,13 +1,29 @@
# Licensed to the Apache Software Foundation (ASF) under one or more
contributor
# license agreements; and to You under the Apache License, Version 2.0.
-# Default values for OpenWhisk.
-# Overall system configuration
+# This file defines the default values for all variables
+# used in the OpenWhisk Helm Chart. The variables are grouped
+# by component into subtrees.
+#
+# You _MUST_ override the default values of whisk.ingress.api_host_name
+# and whisk.ingress.api_host_port (see docs/ingress.md for a discussion
+# of how to determine values for these variables).
+#
+# Production deployments _MUST_ override the default credentials
+# that are used in whisk.auth and db.auth.
+#
+# The file docs/configurationChoices.md discusses other common
+# configuration options for OpenWhisk and which variables to override
+# to enable them.
+
+
+# Overall configuration of the deployment
whisk:
+ # Ingress defines how to access OpenWhisk from outside the Kubernetes
cluster.
+ # See docs/ingress.md for a discussion of how to provide these values.
ingress:
name: "ow-ingress"
- # You _MUST_ provide a value for whisk.ingress.api_host_name and
api_host_port when deploying the chart
api_host_name: nil
api_host_port: nil
api_host_proto: "https"
@@ -66,14 +82,17 @@ kafka:
# Database configuration
db:
+ external: false
name: "couchdb"
image: "openwhisk/kube-couchdb:latest"
replicaCount: 1
imagePullPolicy: "IfNotPresent"
restartPolicy: "Always"
+ host: nil
port: 5984
provider: "CouchDB"
protocol: "http"
+ # Production deployments _MUST_ override the default user/password values
auth:
username: "whisk_admin"
password: "some_passw0rd"
@@ -169,7 +188,10 @@ redis:
storageClass: default
accessMode: ReadWriteOnce
-# Resolve the pod/node affinity for invoker, controller and other components.
+# Used to define pod affinity and anti-affinity for the Kubernetes scheduler.
+# If affinity.enabled is true, then all of the deployments for the OpenWhisk
+# microservices will use node and pod affinity directives to inform the
+# scheduler how to best distribute the pods on the available nodes in the
cluster.
affinity:
enabled: true
coreNodeLabel: core
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