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KPM

KPM is a tool to deploy and manage application stacks on kubernetes.

KPM provides the glue between kubernetes resources (ReplicaSet, DaemonSet, Secrets...). It defines a package as a composition of kubernetes resources and dependencies to other packages.

Versioning and rollbacks

KPM uses a global registry, packages are immediately accessible and visible to the community. Versioning is strong and was easy to implement: https://hub.kubespray.io

Clustered applications and persistent-storage !

• How to scale database slaves(postgresql/mysql/redis) ?
• How to deploy a production-grade elasticsearch/rabbitmq/zookeep/etcd/ clusters on kubernetes? It requires stable network identity and a unique storage per pod!

---> KPM creates multiple variation of a single template with simplicity

Creating a 3 node rabbitmq cluster is easy:

1. List the resources
2. Add the keyword sharded: true to enable unique variation
3. List the shards and define

resources:
  - name: rabbitmq
    file: rabbitmq-rc.yaml
    type: replicationcontroller
    sharded: yes

  - name: rabbitmq
    file: rabbitmq-svc.yaml
    type: service
    sharded: yes

  # LB to any of the rabbitmq shard
  - name: rabbitmq
    file: rabbitmq-umbrella-svc.yaml
    type: service

shards:
  - name: hare
    variables:
      data_volume: {name: data, persistentVolumeClaim: {claimName: claim-hare}}
  - name: bunny
    variables:
      data_volume:  {name: data, persistentVolumeClaim: {claimName: claim-bunny}}
- name: rabbit-on-ram
    variables:
       data_volume: {name: data, emptyDir: ""}
       args: [--ram]

Demo:

Server-side

KPM is an API with an command line interface, its major difference in terms of design and possible integration.

--> We wanted a tool that could be integrated anywhere, for that KPM is building the package server side. Clients are brainless and easy to implement. As a POC we integrated KPM to a fork of https://github.com/kubernetes/dashboard in less than a day: https://youtu.be/7SJ6p38W-WM

Install kpm

From Pypi

kpm is a python2 package and available on pypi

$ sudo pip install kpm -U

From git

git clone https://github.com/kubespray/kpm.git kpm-cli
cd kpm-cli
sudo make install

Configuration

KPM uses kubectl to communicate with the kubernetes cluster. Check if the cluster is accessible:

$ kubectl version
Client Version: version.Info{Major:"1", Minor:"1", GitVersion:"v1.1.4", GitCommit:"a5949fea3a91d6a50f40a5684e05879080a4c61d", GitTreeState:"clean"}
Server Version: version.Info{Major:"1", Minor:"1", GitVersion:"v1.1.4", GitCommit:"a5949fea3a91d6a50f40a5684e05879080a4c61d", GitTreeState:"clean"}

List packages

• All packages: kpm list
• Filter by user: kpm -u username

The website https://kpm.kubespray.io has more advanced search and browsing featutres than the CLI.

Deploy an application

kpm deploy package_name [-v VERSION] [--namespace namespace]

$ kpm deploy ant31/rocketchat --namespace myns
create ant31/rocketchat

package           version    type                   name        namespace    status
----------------  ---------  ---------------------  ----------  -----------  --------
ant31/mongodb     1.0.0      namespace              myns        myns         created
ant31/mongodb     1.0.0      service                mongodb     myns         created
ant31/mongodb     1.0.0      replicationcontroller  mongodb     myns         created
ant31/rocketchat  1.6.2      namespace              myns        myns         ok
ant31/rocketchat  1.6.2      service                rocketchat  myns         created
ant31/rocketchat  1.6.2      replicationcontroller  rocketchat  myns         created

It deploys the package and its dependencies. The command can be executed multiple times, kpm detects changes in resource and apply only the modified ones.

Uninstall an application

The opposite action to deploy is the remove command. It performs a delete on all resources created by deploy. It's possible to mark some resources as protected.

Namespace resources are protected by default.

kpm remove ant31/rocketchat --namespace demo
package           version    type                   name        namespace    status
----------------  ---------  ---------------------  ----------  -----------  ---------
ant31/mongodb     1.0.0      namespace              myns        myns         protected
ant31/mongodb     1.0.0      service                mongodb     myns         deleted
ant31/mongodb     1.0.0      replicationcontroller  mongodb     myns         deleted
ant31/rocketchat  1.6.2      namespace              myns        myns         protected
ant31/rocketchat  1.6.2      service                rocketchat  myns         deleted
ant31/rocketchat  1.6.2      replicationcontroller  rocketchat  myns         deleted