[GitHub] dgrove-oss closed pull request #319: Add entry to values.yaml to configure Kubernetes DNS service

[GitBox <gi...@apache.org>]

dgrove-oss closed pull request #319: Add entry to values.yaml to configure Kubernetes DNS service
URL: https://github.com/apache/incubator-openwhisk-deploy-kube/pull/319
 
 
   

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diff --git a/docs/troubleshooting.md b/docs/troubleshooting.md
index 7b1c863..9dc78fc 100644
--- a/docs/troubleshooting.md
+++ b/docs/troubleshooting.md
@@ -24,7 +24,7 @@ deploying OpenWhisk on Kubernetes and how to correct them.
 
 Verify that you actually have at least one node with the label openwhisk-role=invoker.
 
-### Invokers containers fail to start with volume mounting problems
+### Invoker pods fail to start with volume mounting problems
 
 To execute the containers for user actions, OpenWhisk relies on part
 of the underlying infrastructure that Kubernetes is running on. When
@@ -74,3 +74,16 @@ If you installed self-signed certificates, which is the default
 for the OpenWhisk Helm chart, you will need to use `wsk -i` to
 suppress certificate checking.  This works around `cannot validate
 certificate` errors from the `wsk` CLI.
+
+### nginx pod fails with `host not found in resolver` error
+
+The nginx config map specifies a resolver that is used to resolve references to
+Kubernetes services like the controller and apigateway into ip addresses. By default,
+it uses `kube-dns.kube-system`. If your cluster instead uses `coredns` (or some other
+dns subsystem), you will need to edit the `k8s.dns` entry in values.yaml to
+an appropriate value for your cluster.  A misconfigured resolver will results in
+the nginx pod entering a CrashLoopBackOff with an error message like the one below:
+```
+018/09/27 23:33:48 [emerg] 1#1: host not found in resolver "kube-dns.kube-system" in /etc/nginx/nginx.conf:41
+nginx: [emerg] host not found in resolver "kube-dns.kube-system" in /etc/nginx/nginx.conf:41
+```
diff --git a/helm/openwhisk/templates/nginxConfigMap.yaml b/helm/openwhisk/templates/nginxConfigMap.yaml
index b25140a..f067fb8 100644
--- a/helm/openwhisk/templates/nginxConfigMap.yaml
+++ b/helm/openwhisk/templates/nginxConfigMap.yaml
@@ -51,7 +51,7 @@ data:
         proxy_ssl_verify off;
 
         # Hack to convince nginx to dynamically resolve the dns entries.
-        resolver kube-dns.kube-system;
+        resolver {{ .Values.k8s.dns }};
         set $controllers {{ include "controller_host" . }};
 {{- if or (eq .Values.whisk.ingress.type "NodePort") (eq .Values.whisk.ingress.type "LoadBalancer") }}
         set $apigw {{ include "apigw_host" . }};
diff --git a/helm/openwhisk/values.yaml b/helm/openwhisk/values.yaml
index 7b2b575..34cb6e1 100644
--- a/helm/openwhisk/values.yaml
+++ b/helm/openwhisk/values.yaml
@@ -18,7 +18,7 @@
 # to enable them.
 
 
-# Overall configuration of the deployment
+# Overall configuration of OpenWhisk 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.
@@ -39,6 +39,11 @@ whisk:
   loadbalancer:
     invokerUserMemory: "2048m"
 
+# Properties of the Kubernetes cluster on which OpenWhisk is being deployed
+k8s:
+  domain: cluster.local
+  dns: kube-dns.kube-system
+
 # Images used to run auxillary tasks/jobs
 utility:
   ansibleRunnerImage: "openwhisk/ansible-runner:latest"
@@ -217,6 +222,3 @@ affinity:
   edgeNodeLabel: edge
   invokerNodeLabel: invoker
   providerNodeLabel: provider
-
-k8s:
-  domain: cluster.local


 

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