How can I make sure my health checks work in kubernetes? - kubernetes

I'm currently trying to add health checks into my API through my helm chart. However, when I run this service under kubernetes it seems that my pod is ready but I have 0/1 Running and when I try to hit the URL for the service is not returning anything.
This is how my deployment looks:
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ include "test.fullname" . }}
labels:
app.kubernetes.io/name: {{ include "test.name" . }}
helm.sh/chart: {{ include "test.chart" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
app.kubernetes.io/managed-by: {{ .Release.Service }}
spec:
replicas: {{ .Values.replicaCount }}
selector:
matchLabels:
app.kubernetes.io/name: {{ include "test.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
template:
metadata:
labels:
app.kubernetes.io/name: {{ include "test.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
spec:
containers:
- name: {{ .Chart.Name }}
image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
imagePullPolicy: {{ .Values.image.pullPolicy }}
readinessProbe:
httpGet:
path: /health
port: 8001
initialDelaySeconds: 60
periodSeconds: 60
livenessProbe:
httpGet:
path: /health
port: 8001
initialDelaySeconds: 60
periodSeconds: 60
startupProbe:
httpGet:
path: /health
port: 8001
failureThreshold: 60
periodSeconds: 60
env:
{{- range .Values.variables }}
- name: {{ .name }}
value: {{ .value }}
{{- end }}
ports:
- name: http
containerPort: 80001
protocol: TCP
If I delete the health checks, I will have 1/1 Running. Does anyone knows if I have to add something else to the health checks?

Your healthcheck specification looks syntactically fine.
But your port number seems wrong: The maximum possible TCP port is 65535, you specify 80001. Probably a zero too many?
Verify which port your application is listening to in the container and use that port.
You can verify it by running the app as local docker container and call the health check with curl.

Related

Kubernetes Issue

I have a Micro service (on Node.js)
I am creating a docker image for it and pushing it to my local registry running at
localhost:5001
While deploying this micro service using helm
helm upgrade --install --wait --set env=dev --set image.tag=localhost:5001/user-service userservice-api ./build/helm --namespace dev --create-namespace --kube-context http://localhost:5001
I get
Error: Kubernetes cluster unreachable: context "http://localhost:5001"
does not exist
How do i find out the issue/resolve it?
deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ include "chart.fullname" . }}
labels:
{{- include "chart.labels" . | nindent 4 }}
spec:
{{- if not .Values.autoscaling.enabled }}
replicas: {{ .Values.replicaCount }}
{{- end }}
selector:
matchLabels:
{{- include "chart.selectorLabels" . | nindent 6 }}
template:
metadata:
{{- with .Values.podAnnotations }}
annotations:
{{- toYaml . | nindent 8 }}
{{- end }}
labels:
{{- include "chart.selectorLabels" . | nindent 8 }}
spec:
{{- with .Values.imagePullSecrets }}
imagePullSecrets:
{{- toYaml . | nindent 8 }}
{{- end }}
containers:
- name: {{ .Chart.Name }}
image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
imagePullPolicy: {{ .Values.image.pullPolicy }}
ports:
- name: http
containerPort: 4006
protocol: TCP
env:
- name: ENV
value: "{{ .Values.env }}"
readinessProbe:
httpGet:
path: /health
port: 4006
initialDelaySeconds: 15
periodSeconds: 10
livenessProbe:
httpGet:
path: /health
port: 4006
initialDelaySeconds: 15
periodSeconds: 10
values.yaml
replicaCount: 1
image:
repository: localhost:5001/user-service
Additional Information
Can someone please help me with the issue?
In Dockerfile
RUN npm ci
had to be changed to
In Dockerfile
RUN npm ci --force
resolved issue for me.

helm secrets that replace variables inside configurations files

I am trying to deploy a rest api application in kubernetes with helm. Some of the configuration files have credentials in them and I would like to replace the variables inside the helm templates during the deployment with Kubernetes secrets.
Does anyone have a pointer to a documentation where I can explore this please ?
If you are looking forward to directly deploy the ENV to the deployment file you can also do it if you can few environment variables however best practices to create the secret and inject them all into the deployment.
here sharing the direct example to inject the secret into the deployment
deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: "{{ .Chart.Name }}-deployment"
labels:
chart: '{{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}'
spec:
replicas: {{ .Values.replicaCount }}
strategy:
type: RollingUpdate
rollingUpdate:
maxUnavailable: 0
maxSurge: 1
selector:
matchLabels:
app: "{{ .Chart.Name }}-selector"
version: "current"
revisionHistoryLimit: {{ .Values.revisionHistoryLimit }}
template:
metadata:
labels:
app: "{{ .Chart.Name }}-selector"
version: "current"
spec:
containers:
- name: "{{ .Chart.Name }}"
image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
imagePullPolicy: {{ .Values.image.pullPolicy }}
ports:
- containerPort: {{ .Values.service.servicePort}}
resources:
requests:
cpu: "{{ .Values.image.resources.requests.cpu }}"
memory: "{{ .Values.image.resources.requests.memory }}"
env:
- name: PORT
value : "{{ .Values.service.servicePort }}"
{{- if .Values.image.livenessProbe }}
livenessProbe:
{{ toYaml .Values.image.livenessProbe | indent 10 }}
{{- end }}
{{- if .Values.image.readinessProbe }}
readinessProbe:
{{ toYaml .Values.image.readinessProbe | indent 10 }}
{{- end }}
values.yaml
image:
repository: nodeserver
tag: 1.0.0
pullPolicy: IfNotPresent
resources:
requests:
cpu: 200m
memory: 300Mi
readinessProbe: {}
# Example (replace readinessProbe: {} with the following):
# readinessProbe:
# httpGet:
# path: /ready
# port: 3000
# initialDelaySeconds: 3
# periodSeconds: 5
livenessProbe: {}
# Example (replace livenessProbe: {} with the following)::
# livenessProbe:
# httpGet:
# path: /live
# port: 3000
# initialDelaySeconds: 40
# periodSeconds: 10
service:
name: Node
type: NodePort
servicePort: 3000
you can see inside the deployment.yaml code block
env:
- name: PORT
value : "{{ .Values.service.servicePort }}"
it's fetching the values from values.yaml file
service:
name: Node
type: NodePort
servicePort: 3000
if you don't want to update the values.yaml file you can rewrite the value using the command also
helm install chart my-chart -n namespace-name --set service.servicePort=5000
Create a Secret template in your templates folder. Then, you can pass the values through helm cli.
For example, here is my secret.yaml file.
apiVersion: v1
kind: Secret
metadata:
name: mysecret
type: Opaque
data:
password: {{ .Values.password | b64enc }}
Now, I can set the value for password as bellow:
helm install my-chart-instance my-chart -n my-namespace --set password=my-secret-value

Kubernetes requests not balanced

We've just had an increase in traffic to our kubernetes cluster and I've noticed that of our 6 application pods, 2 of them are seemingly not used very much. kubectl top pods returns the following
You can see of the 6 pods, 4 of them are using more than 50% of the CPU (2 vCPU nodes), but two of them aren't really doing much at all.
Our cluster is setup on AWS, using the ALB ingress controller. The load balancer is configured to use the Least outstanding requests rather than Round robin in an attempt to balance things out a bit more, but we're still seeing this imbalance.
Is there any way of determining why this is happening, or if indeed it actually is a problem? I'm hoping it's normal behaviour rather than an issue but I'd rather investigate it.
App deployment config
This is the configuration of the main application pods. Nothing fancy really
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ include "app.fullname" . }}
labels:
{{- include "app.labels" . | nindent 4 }}
app.kubernetes.io/component: web
spec:
replicas: {{ .Values.app.replicaCount }}
selector:
matchLabels:
app: {{ include "app.fullname" . }}-web
template:
metadata:
annotations:
checksum/config: {{ include (print $.Template.BasePath "/config_maps/app-env-vars.yaml") . | sha256sum }}
{{- with .Values.podAnnotations }}
{{- toYaml . | nindent 10 }}
{{- end }}
labels:
{{- include "app.selectorLabels" . | nindent 8 }}
app.kubernetes.io/component: web
app: {{ include "app.fullname" . }}-web
spec:
serviceAccountName: {{ .Values.serviceAccount.web }}
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- weight: 100
podAffinityTerm:
labelSelector:
matchExpressions:
- key: app
operator: In
values:
- {{ include "app.fullname" . }}-web
topologyKey: failure-domain.beta.kubernetes.io/zone
containers:
- name: {{ .Values.image.name }}
image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
imagePullPolicy: {{ .Values.image.pullPolicy }}
command:
- bundle
args: ["exec", "puma", "-p", "{{ .Values.app.containerPort }}"]
ports:
- name: http
containerPort: {{ .Values.app.containerPort }}
protocol: TCP
readinessProbe:
httpGet:
path: /healthcheck
port: {{ .Values.app.containerPort }}
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 5
timeoutSeconds: 5
resources:
{{- toYaml .Values.resources | nindent 12 }}
envFrom:
- configMapRef:
name: {{ include "app.fullname" . }}-cm-env-vars
- secretRef:
name: {{ include "app.fullname" . }}-secret-rails-master-key
- secretRef:
name: {{ include "app.fullname" . }}-secret-db-credentials
- secretRef:
name: {{ include "app.fullname" . }}-secret-db-url-app
- secretRef:
name: {{ include "app.fullname" . }}-secret-redis-credentials
That's a known issue with Kubernetes.
In short, Kubernetes doesn't load balance long-lived TCP connections.
This excellent article covers it in details.
The load distribution you service is showing complies exactly with the case.

acumos AI clio installation fails with "error converting YAML to JSON"

I have been trying to install clio release.
VM :
ubuntu 18.04
16 Cores
32 GB RAM
500 GB Storage.
Command :
bash /home/ubuntu/system-integration/tools/aio_k8s_deployer/aio_k8s_deployer.sh all acai-server ubuntu generic
All most all steps of installation have completed successfully but during "setup-lum", I got below error.
Error:
YAML parse error on lum-helm/templates/deployment.yaml:
error converting YAML to JSON: yaml: line 36: mapping values are not allowed in this context
Workaround :
I was able to get away with these error(tested via helm install --dry-run ) by
a. removing "resource, affinity and tolerant blocks
b. replace "Release.Name" with actual release value( e.g. license-clio-configmap)
but when I run the full installation command, those helms charts are updated again.
Full error :
...
helm install -f kubernetes/values.yaml --name license-clio --namespace default --debug ./kubernetes/license-usage-manager/lum-helm
[debug] Created tunnel using local port: '46109'
[debug] SERVER: "127.0.0.1:46109"
[debug] Original chart version: ""
[debug] CHART PATH: /deploy/system-integration/AIO/lum/kubernetes/license-usage-manager/lum-helm
YAML parse error on lum-helm/templates/deployment.yaml: error converting YAML to JSON: yaml: line 36: mapping values are not allowed in this context
Yaml of deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ template "lum-helm.fullname" . }}
labels:
app: {{ template "lum-helm.name" . }}
chart: {{ template "lum-helm.chart" . }}
release: {{ .Release.Name }}
heritage: {{ .Release.Service }}
spec:
replicas: {{ .Values.replicaCount }}
selector:
matchLabels:
app: {{ template "lum-helm.name" . }}
release: {{ .Release.Name }}
template:
metadata:
labels:
app: {{ template "lum-helm.name" . }}
release: {{ .Release.Name }}
spec:
initContainers:
- name: wait-for-db
image: busybox:1.28
command:
- 'sh'
- '-c'
- >
until nc -z -w 2 {{ .Release.Name }}-postgresql {{ .Values.postgresql.servicePort }} && echo postgresql ok;
do sleep 2;
done
containers:
- name: {{ .Chart.Name }}
image: nexus3.acumos.org:10002/acumos/lum-server:default
imagePullPolicy: {{ .Values.image.pullPolicy }}
env:
- name: DATABASE_PASSWORD
valueFrom:
secretKeyRef:
name: {{ .Release.Name }}-postgresql
key: postgresql-password
- name: NODE
volumeMounts:
- name: config-volume
mountPath: /opt/app/lum/etc/config.json
subPath: lum-config.json
ports:
- name: http
containerPort: 2080
protocol: TCP
livenessProbe:
httpGet:
path: '/api/healthcheck'
port: http
initialDelaySeconds: 60
periodSeconds: 10
failureThreshold: 10
readinessProbe:
httpGet:
path: '/api/healthcheck'
port: http
initialDelaySeconds: 60
periodSeconds: 10
failureThreshold: 10
resources:
{{ toYaml .Values.resources | indent 12 }}
{{- with .Values.nodeSelector }}
nodeSelector:
{{ toYaml . | indent 8 }}
{{- end }}
{{- with .Values.affinity }}
affinity:
{{ toYaml . | indent 8 }}
{{- end }}
{{- with .Values.tolerations }}
tolerations:
{{ toYaml . | indent 8 }}
{{- end }}
volumes:
- name: config-volume
configMap:
name: {{ .Release.Name }}-configmap
This error was resolved as per Error trying to install Acumos Clio using AIO
I provided an imagetag:1.3.2 in my actual value.yaml and lum deployment was successful
in acumos setup there are two copied of setup-lum.sh and values.yaml
actual :
~/system-integration/AIO/lum/kubernetes/value.yaml
and run time copy
~/aio_k8s_deployer/deploy/system-integration/AIO/lum/kubernetes/value.yaml
I found this workaround:
Uncommented the IMAGE-TAG line in the values.yaml file
Commented the following lines in the setup-lum.sh file (these were already executed at the first run and in this way I skipped the overwriting problem)
rm -frd kubernetes/license-usage-manager
git clone "https://gerrit.acumos.org/r/license-usage-manager" \
kubernetes/license-usage-manager

Knative service with Keycloak gatekeeper sidecar

I am trying to deploy the following service:
{{- if .Values.knativeDeploy }}
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
{{- if .Values.service.name }}
name: {{ .Values.service.name }}
{{- else }}
name: {{ template "fullname" . }}
{{- end }}
labels:
chart: "{{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}"
spec:
template:
spec:
containers:
- image: quay.io/keycloak/keycloak-gatekeeper:9.0.3
name: gatekeeper-sidecar
ports:
- containerPort: {{ .Values.keycloak.proxyPort }}
env:
- name: KEYCLOAK_CLIENT_SECRET
valueFrom:
secretKeyRef:
name: {{ template "keycloakclient" . }}
key: secret
args:
- --resources=uri=/*
- --discovery-url={{ .Values.keycloak.url }}/auth/realms/{{ .Values.keycloak.realm }}
- --client-id={{ template "keycloakclient" . }}
- --client-secret=$(KEYCLOAK_CLIENT_SECRET)
- --listen=0.0.0.0:{{ .Values.keycloak.proxyPort }} # listen on all interfaces
- --enable-logging=true
- --enable-json-logging=true
- --upstream-url=http://127.0.0.1:{{ .Values.service.internalPort }} # To connect with the main container's port
resources:
{{ toYaml .Values.gatekeeper.resources | indent 12 }}
- name: {{ .Chart.Name }}
image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
imagePullPolicy: {{ .Values.image.pullPolicy }}
env:
{{- range $pkey, $pval := .Values.env }}
- name: {{ $pkey }}
value: {{ quote $pval }}
{{- end }}
envFrom:
{{ toYaml .Values.envFrom | indent 10 }}
ports:
- containerPort: {{ .Values.service.internalPort }}
livenessProbe:
httpGet:
path: {{ .Values.probePath }}
port: {{ .Values.service.internalPort }}
initialDelaySeconds: {{ .Values.livenessProbe.initialDelaySeconds }}
periodSeconds: {{ .Values.livenessProbe.periodSeconds }}
successThreshold: {{ .Values.livenessProbe.successThreshold }}
timeoutSeconds: {{ .Values.livenessProbe.timeoutSeconds }}
readinessProbe:
httpGet:
path: {{ .Values.probePath }}
port: {{ .Values.service.internalPort }}
periodSeconds: {{ .Values.readinessProbe.periodSeconds }}
successThreshold: {{ .Values.readinessProbe.successThreshold }}
timeoutSeconds: {{ .Values.readinessProbe.timeoutSeconds }}
resources:
{{ toYaml .Values.resources | indent 12 }}
terminationGracePeriodSeconds: {{ .Values.terminationGracePeriodSeconds }}
{{- end }}
Which fails with the following error:
Error from server (BadRequest): error when creating "/tmp/helm-template-workdir-290082188/jx/output/namespaces/jx-staging/env/charts/docs/templates/part0-ksvc.yaml": admission webhook "webhook.serving.knative.dev" denied the request: mutation failed: expected exactly one, got both: spec.template.spec.containers'
Now, if I read the specs (https://knative.dev/v0.15-docs/serving/getting-started-knative-app/), I can see this example:
apiVersion: serving.knative.dev/v1 # Current version of Knative
kind: Service
metadata:
name: helloworld-go # The name of the app
namespace: default # The namespace the app will use
spec:
template:
spec:
containers:
- image: gcr.io/knative-samples/helloworld-go # The URL to the image of the app
env:
- name: TARGET # The environment variable printed out by the sample app
value: "Go Sample v1"
Which has exactly the same structure. Now, my questions are:
How can I validate my yam without waiting for a deployment? Intellij has a k8n plugin, but I can't find the CRD schema for serving.knative.dev/v1 that are machine consumable. (https://knative.dev/docs/serving/spec/knative-api-specification-1.0/)
Is it allowed with knative to have multiple container? (that configuration works perfectly with apiVersion: apps/v1 kind: Deployment)
Multi container is alpha feature in knative version 0.16.
This feature need to be enabled by setting multi-container to enabled in the config-features ConfigMap. So edit the configmap using
kubectl edit cm config-features and enable that feature.
apiVersion: v1
kind: ConfigMap
metadata:
name: config-features
namespace: knative-serving
labels:
serving.knative.dev/release: devel
annotations:
knative.dev/example-checksum: "983ddf13"
data:
_example: |
...
# Indicates whether multi container support is enabled
multi-container: "enabled"
...
What version of Knative are you using?
Support for multiple containers was added as an alpha feature in 0.16. If you're not using 0.16 or later or don't have the alpha flag enabled, the request will probably be blocked.
There were a number of edge cases to define for multi-container support in Knative, so the default was to be conservative and only allow one container until the constraints had been explored.