[Kubernetes] Kubernetes documentation
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Kubernetes/README.rst
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Kubernetes/README.rst
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Google Kubernetes for Murano
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============================
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Packages in this folder are required to deploy both Google Kubernetes and
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applications on top of it.
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Contents of each folder need to be zipped and uploaded to Murano Catalog.
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You will also need to build proper Ubuntu image for Kubernetes.
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This can be done using diskimage-builder (https://github.com/openstack/diskimage-builder)
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and DIB elements (https://github.com/stackforge/murano/tree/master/contrib/elements/kubernetes).
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The image must has name ubuntu14.04-x64-kubernetes.qcow2
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Kubernetes is an open-source container manager by Google. It is responsible to
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schedule, run and manage docker containers into its own clustered setup.
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Kubernetes consists of one or more master nodes running Kubernetes API and
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one or more worker nodes (aka minions) that are used to schedule containers.
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Containers are aggregated into pods. All containers in single pod are
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guaranteed to be scheduled to a single node and share common port space.
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Thus it can be considered as a container colocation.
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Pods can be replicated. This is achieved by creation of Replication Controller
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which creates and maintain fixed number of pod clones. In Murano replica
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count is a property of KubernetesPod.
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Currently Murano suports setups with only single API node and at least one
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worker node. API node cannot be used as a worker node.
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To establish required network connectivity model for the Kubernetes Murano
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sets up an overlay network between Kubernetes nodes using Flannel networking.
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See https://github.com/coreos/flannel for more information.
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Because IP addresses of containers are in that internal network and not
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accessible from outside in order to provide public endpoints Murano sets up
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a third type of nodes: Gateway nodes.
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Gateway nodes are connected to both Flannel and OpenStack Neutron networks
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and serves as a gateway between them. Each gateway node runs HAProxy.
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When application deploys all its public endpoint are automatically registered
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on all gateway nodes. Thus if user chose to have more than one gateway
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it will usually get several endpoints for the application. Then those endpoints
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can be registered in physical load balancer or DNS.
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KubernetesCluster
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=================
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This is the main application representing Kubernetes Cluster.
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It is responsible for deployment of the Kubernetes and its nodes.
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The procedure is:
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#. Create VMs for all node types - 1 for Kubernetes API and requested number
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for worker and gateway nodes.
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#. Join them into etcd cluster. etcd is a distributed key-value storage
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used by the Kubernetes to store and synchronize cluster state.
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#. Setup Flannel network over etcd cluster. Flannel uses etcd to track network.
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nodes as well.
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#. Configure required services on master node.
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#. Configure worker nodes. They will register themselves in master nodes using
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etcd.
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#. Setup HAProxy on each gateway node. Configure configd to watch etcd to
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register public ports in HAProxy config file. Each time new Kubernetes
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service created it regenerates HAProxy config.
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Internally KubernetesCluster contains separate classes for all node types.
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They all inherit from `KubernetesNode` that defines the common interface
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for all nodes. The deployment of each node is split into several methods:
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`deployInstance` -> `setupEtcd` -> `setupNode` -> `removeFromCluster` as
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described above.
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KubernetesPod
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=============
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KubernetesPod represents a single Kubernetes pod with its containers and
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associated volumes. KubernetesPod provides an implementation of
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`DockerContainerHost` interface defined in `DockerInterfacesLibrary`.
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Thus each pod can be used as a drop-in replacement for regular Docker
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host implementation (DockerStandaloneHost).
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All pods must have a unique name within single `KubernetesCluster`
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(which is selected for each pod).
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Thus KubernetesCluster is an aggregation of Docker hosts (pods) which also
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handles all inter-pod entities (services, endpoints).
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KubernetesPod create Replication Controllers rather than pods. Replication
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Controller with replica count equal to 1 will result in single pod being
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created while it is always possible to increase/decrease replica count after
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deployment. Replica count is specified using `replicas` input property.
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Pods also may have labels to group them (for example into layers etc.)
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Kubernetes actions
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==================
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Both KubernetesCluster and KubernetesPod expose number of actions that can
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be used by both user (through the dashboard) and automation systems (through
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API) to perform actions on the deployed applications.
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See http://docs.openstack.org/developer/murano/draft/appdev-guide/murano_pl.html#murano-actions
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and http://docs.openstack.org/developer/murano/specification/index.html#actions-api
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for more details on actions API.
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KubernetesCluster provides the following actions:
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* `scaleNodesUp`: increase the number of worker nodes by 1.
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* `scaleNodesDown`: decrease the number of worker nodes by 1.
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* `scaleGatewaysUp`: increase the number of gateway nodes by 1.
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* `scaleGatewaysDown`: decrease the number of gateway nodes by 1.
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* `exportConfig`: returns an archive file containing shell script and data
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files. Use the script to manually recreate Kubernetes entities (pods,
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replication controllers and services) on another Kubernetes installation.
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This is an experimental feature.
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KubernetesPod has the following actions:
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* `scalePodUp`: increase the number of pod replicas by 1.
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* `scalePodDown`: decrease the number of pod replicas by 1.
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@ -1,52 +0,0 @@
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# Google Kubernetes for Murano
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Packages in this folder are required to deploy both Google Kubernetes and applications
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on top of it.
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Contents of each folder need to be zipped and uploaded to Murano Application Catalog.
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You will also need to build proper Ubuntu image for Kubernetes.
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This can be done using diskimage-builder (https://github.com/openstack/diskimage-builder) and
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DIB elements (https://github.com/stackforge/murano/tree/master/contrib/elements/kubernetes).
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Applications expect the following images:
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* ubuntu14.04-x64-kubernetes.qcow2 for Kubernetes
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* ubuntu14.04-x64-docker.qcow2 for Docker
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Brief description of packages located here:
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io.murano.apps.docker.kubernetes.KubernetesCluster – represents scalable
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cluster of Kubernetes nodes
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io.murano.apps.docker.kubernetes.KubernetesPod – Kubernetes host for Docker
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containers. Several containers may be hosted in single Pod. Also
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automatically manages Service endpoints and replication
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io.murano.apps.docker.Interfaces – Interface classes for both Kubernetes and Docker
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io.murano.apps.docker.kubernetes.static.KubernetesEntities – Kubernetes
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instances that can be constructed from a JSON definition – Pod, Service
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and ReplicationController
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io.murano.apps.docker.DockerStandaloneHost - Docker host on standalone VM
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Applications that can be hosted on both Kubernetes Pod and and Docker standalone host:
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* io.murano.apps.docker.DockerHTTPd – Apache web server
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* io.murano.apps.docker.DockerHTTPdSite – Apache web server with a site pulled from git repository
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* io.murano.apps.docker.DockerNginx – Nginx web server
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* io.murano.apps.docker.DockerNginxSite – Nginx web server with a site pulled from git repository
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* io.murano.apps.docker.DockerCrate - Crate - The Distributed Database for Docker
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* io.murano.apps.docker.DockerGlassFish - GlassFish - Java EE 7 Application Server
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* io.murano.apps.docker.DockerTomcat - Tomcat - An open-source web server and servlet container
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* io.murano.apps.docker.DockerInfluxDB - InfluxDB - An open-source, distributed, time series database
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* io.murano.apps.docker.DockerGrafana - Grafana - Metrics dashboard for InfluxDB
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* io.murano.apps.docker.DockerJenkins - Jenkins - An extensible open source continuous integration server
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* io.murano.apps.docker.DockerMariaDB - MariaDB database
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* io.murano.apps.docker.DockerMySQL - MySql database
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* io.murano.apps.docker.DockerRedis - Redis - Key-value cache and store
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* io.murano.apps.docker.DockerPostgreSQL - PostgreSQL database
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* io.murano.apps.docker.DockerMongoDB - MongoDB NoSQL database
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* io.murano.apps.docker.DockerPHPZendServer - Zend Server - The Complete PHP Application Platform
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@ -24,6 +24,7 @@ run Docker applications:
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* Kubernetes: an open source container cluster manager by Google. It allows
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to schedule and run Docker applications on multiple clustered nodes.
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Application both installs Kubernetes and provides capabilities to run
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Docker applications similar to DockerStandaloneHost.
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Docker applications similar to DockerStandaloneHost. See
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Kubernetes/README.rst for more details.
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* Applications: Examples of some of the most popular Docker applications.
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