321 lines
11 KiB
Markdown
321 lines
11 KiB
Markdown
---
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assignees:
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- jdef
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- karlkfi
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title: Kubernetes on Mesos on Docker
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---
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The mesos/docker provider uses docker-compose to launch Kubernetes as a Mesos framework, running in docker with its
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dependencies (etcd & mesos).
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* TOC
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{:toc}
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## Cluster Goals
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- kubernetes development
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- pod/service development
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- demoing
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- fast deployment
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- minimal hardware requirements
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- minimal configuration
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- entry point for exploration
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- simplified networking
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- fast end-to-end tests
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- local deployment
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Non-Goals:
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- high availability
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- fault tolerance
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- remote deployment
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- production usage
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- monitoring
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- long running
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- state persistence across restarts
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## Cluster Topology
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The cluster consists of several docker containers linked together by docker-managed hostnames:
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| Component | Hostname | Description |
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|-------------------------------|-----------------------------|-----------------------------------------------------------------------------------------|
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| docker-grand-ambassador | | Proxy to allow circular hostname linking in docker |
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| etcd | etcd | Key/Value store used by Mesos |
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| Mesos Master | mesosmaster1 | REST endpoint for interacting with Mesos |
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| Mesos Slave (x2) | mesosslave1, mesosslave2 | Mesos agents that offer resources and run framework executors (e.g. Kubernetes Kublets) |
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| Kubernetes API Server | apiserver | REST endpoint for interacting with Kubernetes |
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| Kubernetes Controller Manager | controller | |
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| Kubernetes Scheduler | scheduler | Schedules container deployment by accepting Mesos offers |
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## Prerequisites
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Required:
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- [Git](https://git-scm.com/book/en/v2/Getting-Started-Installing-Git) - version control system
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- [Docker CLI](https://docs.docker.com/) - container management command line client
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- [Docker Engine](https://docs.docker.com/) - container management daemon
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- On Mac, use [Docker Machine](https://docs.docker.com/machine/install-machine/)
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- [Docker Compose](https://docs.docker.com/compose/install/) - multi-container application orchestration
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Optional:
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- [Virtual Box](https://www.virtualbox.org/wiki/Downloads)
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- Free x86 virtualization engine with a Docker Machine driver
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- [Golang](https://golang.org/doc/install) - Go programming language
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- Required to build Kubernetes locally
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- [Make](https://en.wikipedia.org/wiki/Make_(software)) - Utility for building executables from source
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- Required to build Kubernetes locally with make
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### Install on Mac (Homebrew)
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It's possible to install all of the above via [Homebrew](http://brew.sh/) on a Mac.
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Some steps print instructions for configuring or launching. Make sure each is properly set up before continuing to the next step.
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```shell
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brew install git
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brew install caskroom/cask/brew-cask
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brew cask install virtualbox
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brew install docker
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brew install docker-machine
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brew install docker-compose
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```
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### Install on Linux
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Most of the above are available via apt and yum, but depending on your distribution, you may have to install via other
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means to get the latest versions.
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It is recommended to use Ubuntu, simply because it best supports AUFS, used by docker to mount volumes. Alternate file
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systems may not fully support docker-in-docker.
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In order to build Kubernetes, the current user must be in a docker group with sudo privileges.
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See the docker docs for [instructions](https://docs.docker.com/installation/ubuntulinux/#create-a-docker-group).
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#### Docker Machine Config (Mac)
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If on a Mac using docker-machine, the following steps will make the docker IPs (in the virtualbox VM) reachable from the
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host machine (Mac).
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1. Create VM
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oracle-virtualbox
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```shell
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docker-machine create --driver virtualbox kube-dev
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eval "$(docker-machine env kube-dev)"
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```
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2. Set the VM's host-only network to "promiscuous mode":
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oracle-virtualbox
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```conf
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docker-machine stop kube-dev
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VBoxManage modifyvm kube-dev --nicpromisc2 allow-all
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docker-machine start kube-dev
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```
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This allows the VM to accept packets that were sent to a different IP.
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Since the host-only network routes traffic between VMs and the host, other VMs will also be able to access the docker
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IPs, if they have the following route.
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1. Route traffic to docker through the docker-machine IP:
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```shell
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sudo route -n add -net 172.17.0.0 $(docker-machine ip kube-dev)
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```
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Since the docker-machine IP can change when the VM is restarted, this route may need to be updated over time.
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To delete the route later: `sudo route delete 172.17.0.0`
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## Walkthrough
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1. Checkout source
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```shell
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git clone https://github.com/kubernetes/kubernetes
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cd kubernetes
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```
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By default, that will get you the bleeding edge of master branch.
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You may want a [release branch](https://github.com/kubernetes/kubernetes/releases) instead,
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if you have trouble with master.
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1. Build binaries
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You'll need to build kubectl (CLI) for your local architecture and operating system and the rest of the server binaries for linux/amd64.
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Building a new release covers both cases:
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```shell
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KUBERNETES_CONTRIB=mesos build/release.sh
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```
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For developers, it may be faster to [build locally](#build-locally).
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1. [Optional] Build docker images
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The following docker images are built as part of `./cluster/kube-up.sh`, but it may make sense to build them manually the first time because it may take a while.
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1. Test image includes all the dependencies required for running e2e tests.
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```shell
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./cluster/mesos/docker/test/build.sh
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```
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In the future, this image may be available to download. It doesn't contain anything specific to the current release, except its build dependencies.
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1. Kubernetes-Mesos image includes the compiled linux binaries.
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```shell
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./cluster/mesos/docker/km/build.sh
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```
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This image needs to be built every time you recompile the server binaries.
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1. [Optional] Configure Mesos resources
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By default, the mesos-slaves are configured to offer a fixed amount of resources (cpus, memory, disk, ports).
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If you want to customize these values, update the `MESOS_RESOURCES` environment variables in `./cluster/mesos/docker/docker-compose.yml`.
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If you delete the `MESOS_RESOURCES` environment variables, the resource amounts will be auto-detected based on the host resources, which will over-provision by > 2x.
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If the configured resources are not available on the host, you may want to increase the resources available to Docker Engine.
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You may have to increase you VM disk, memory, or cpu allocation. See the Docker Machine docs for details
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([Virtualbox](https://docs.docker.com/machine/drivers/virtualbox))
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1. Configure provider
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```shell
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export KUBERNETES_PROVIDER=mesos/docker
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```
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This tells cluster scripts to use the code within `cluster/mesos/docker`.
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1. Create cluster
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```shell
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./cluster/kube-up.sh
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```
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If you manually built all the above docker images, you can skip that step during kube-up:
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```shell
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MESOS_DOCKER_SKIP_BUILD=true ./cluster/kube-up.sh
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```
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After deploying the cluster, `~/.kube/config` will be created or updated to configure kubectl to target the new cluster.
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1. Explore examples
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To learn more about Pods, Volumes, Labels, Services, and Replication Controllers, start with the
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[Kubernetes Walkthrough](/docs/user-guide/walkthrough/).
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To skip to a more advanced example, see the [Guestbook Example](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/examples/guestbook/)
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1. Destroy cluster
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```shell
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./cluster/kube-down.sh
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```
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## Addons
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The `kube-up` for the mesos/docker provider will automatically deploy KubeDNS and KubeUI addons as pods/services.
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Check their status with:
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```shell
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./cluster/kubectl.sh get pods --namespace=kube-system
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```
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### KubeUI
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The web-based Kubernetes UI is accessible in a browser through the API Server proxy: `https://<apiserver>:6443/ui/`.
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By default, basic-auth is configured with user `admin` and password `admin`.
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The IP of the API Server can be found using `./cluster/kubectl.sh cluster-info`.
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## End To End Testing
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Warning: e2e tests can take a long time to run. You may not want to run them immediately if you're just getting started.
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While your cluster is up, you can run the end-to-end tests:
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```shell
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./cluster/test-e2e.sh
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```
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Notable parameters:
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- Increase the logging verbosity: `-v=2`
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- Run only a subset of the tests (regex matching): `-ginkgo.focus=<pattern>`
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To build, deploy, test, and destroy, all in one command (plus unit & integration tests):
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```shell
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make test_e2e
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```
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## Kubernetes CLI
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When compiling from source, it's simplest to use the `./cluster/kubectl.sh` script, which detects your platform &
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architecture and proxies commands to the appropriate `kubectl` binary.
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ex: `./cluster/kubectl.sh get pods`
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## Helpful scripts
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- Kill all docker containers
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```shell
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docker ps -q -a | xargs docker rm -f
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```
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- Clean up unused docker volumes
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```shell
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docker run -v /var/run/docker.sock:/var/run/docker.sock -v /var/lib/docker:/var/lib/docker --rm martin/docker-cleanup-volumes
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```
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## Build Locally
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The steps above tell you how to build in a container, for minimal local dependencies. But if you have Go and Make installed you can build locally much faster:
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```shell
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KUBERNETES_CONTRIB=mesos make
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```
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However, if you're not on linux, you'll still need to compile the linux/amd64 server binaries:
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```shell
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KUBERNETES_CONTRIB=mesos build/run.sh hack/build-go.sh
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```
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The above two steps should be significantly faster than cross-compiling a whole new release for every supported platform (which is what `./build/release.sh` does).
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Breakdown:
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- `KUBERNETES_CONTRIB=mesos` - enables building of the contrib/mesos binaries
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- `hack/build-go.sh` - builds the Go binaries for the current architecture (linux/amd64 when in a docker container)
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- `make` - delegates to `hack/build-go.sh`
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- `build/run.sh` - executes a command in the build container
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- `build/release.sh` - cross compiles Kubernetes for all supported architectures and operating systems (slow)
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## Support Level
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IaaS Provider | Config. Mgmt | OS | Networking | Docs | Conforms | Support Level
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-------------------- | ------------ | ------ | ---------- | --------------------------------------------- | ---------| ----------------------------
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Mesos/Docker | custom | Ubuntu | Docker | [docs](/docs/getting-started-guides/mesos-docker) | | Community ([Kubernetes-Mesos Authors](https://github.com/mesosphere/kubernetes-mesos/blob/master/AUTHORS.md))
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For support level information on all solutions, see the [Table of solutions](/docs/getting-started-guides/#table-of-solutions) chart.
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