deprecated-helm-charts/stable/memcached

⚠️ Repo Archive Notice

As of Nov 13, 2020, charts in this repo will no longer be updated. For more information, see the Helm Charts Deprecation and Archive Notice, and Update.

Memcached

Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.

Based on the memcached chart from the Bitnami Charts repository.

DEPRECATION NOTICE

This chart is deprecated and no longer supported.

TL;DR;

$ helm install stable/memcached

Introduction

This chart bootstraps a Memcached deployment on a Kubernetes cluster using the Helm package manager.

Installing the Chart

To install the chart with the release name my-release:

$ helm install --name my-release stable/memcached

The command deploys Memcached on the Kubernetes cluster in the default configuration. The configuration section lists the parameters that can be configured during installation.

Tip

: List all releases using helm list

Uninstalling the Chart

To uninstall/delete the my-release deployment:

$ helm delete my-release

The command removes all the Kubernetes components associated with the chart and deletes the release.

Configuration

The following table lists the configurable parameters of the Memcached chart and their default values.

Parameter	Description	Default
image	The image to pull and run	A recent official memcached tag
imagePullPolicy	Image pull policy	Always if imageTag is latest, else IfNotPresent
memcached.verbosity	Verbosity level (v, vv, or vvv)	Un-set.
memcached.maxItemMemory	Max memory for items (in MB)	64
memcached.extraArgs	Additional memcached arguments	[]
metrics.enabled	Expose metrics in prometheus format	false
metrics.serviceMonitor.enabled	Expose serviceMonitor to be scraped in prometheus-operator target	false
metrics.serviceMonitor.interval	Default frequency to scrap metrics	15s
metrics.image	The image to pull and run for the metrics exporter	A recent official memcached tag
metrics.imagePullPolicy	Image pull policy	Always if imageTag is latest, else IfNotPresent
metrics.resources	CPU/Memory resource requests/limits for the metrics exporter	{}
extraContainers	Container sidecar definition(s) as string	Un-set
extraVolumes	Volume definitions to add as string	Un-set
kind	Install as StatefulSet or Deployment	StatefulSet
podAnnotations	Map of annotations to add to the pod(s)	{}
podLabels	Custom Labels to be applied to statefulset	Un-set
nodeSelector	Simple pod scheduling control	{}
tolerations	Allow or deny specific node taints	{}
affinity	Advanced pod scheduling control	{}
securityContext.enabled	Enable security context	true
securityContext.fsGroup	Group ID for the container	1001
securityContext.runAsUser	User ID for the container	1001
updateStrategy.type	Update strategy for the StatefulSet/Deployment	RollingUpdate
priorityClassName	Specifies the pod's priority class name	Un-set

The above parameters map to memcached params. For more information please refer to the Memcached documentation.

Specify each parameter using the --set key=value[,key=value] argument to helm install. For example,

$ helm install --name my-release \
  --set memcached.verbosity=v \
    stable/memcached

The above command sets the Memcached verbosity to v.

Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,

$ helm install --name my-release -f values.yaml stable/memcached

Tip

: You can use the default values.yaml

Upgrading to 3.x from a previous major version

Version 3.0.0 of this chart makes an incompatible change to the way StatefulSet/Deployment selectors are configured. If you try to upgrade from a previous major version, you will see an error like this:

Error: UPGRADE FAILED: Deployment.apps "mc-test-memcached" is invalid: spec.template.metadata.labels: Invalid value: map[string]string{"app":"mc-test-memcached", "chart":"memcached-3.0.0", "custom":"value", "heritage":"Tiller", "release":"mc-test"}: `selector` does not match template `labels`

To upgrade from a previous major version, you'll either need to perform a small manual fix or delete and reinstall the chart.

Upgrading with kind: StatefulSet

If you're using a StatefulSet, you'll have to manually delete it and allow Helm to re-create it. Run kubectl delete --cascade=false sts name-goes-here to delete the StatefulSet without deleting the pods. Once you've done this, upgrade the chart as normal, and the newly-created StatefulSet will adopt the old pods.

Upgrading with kind: Deployment

If you're using a Deployment, the manual fix is to remove all selectors from the spec except app and release. Run kubectl edit deploy name-goes-here, and you should see a part like this in your editor about 20 lines down:

spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 2
  selector:
    matchLabels:
      app: mc-test-memcached
      chart: memcached-2.10.2
      heritage: Tiller
      release: mc-test

Remove the lines under matchLabels except app: ... and release: ..., and don't change any other lines. The part from above should look like this when you're done:

spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 2
  selector:
    matchLabels:
      app: mc-test-memcached
      release: mc-test

Once you've done this, you can upgrade to 3.x with Helm as normal.

If you want prometheus-operator scrap all serviceMonitors in your cluster you need to set:

prometheus:
  prometheusSpec:
    serviceMonitorSelectorNilUsesHelmValues: false

If you want to be specific:

prometheus:
  prometheusSpec:
    serviceMonitorSelector:
      matchLabels:
        app: memcached

You can have more intel in prometheus-operator values and here github