118 lines
5.3 KiB
Markdown
118 lines
5.3 KiB
Markdown
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# cri-o - OCI-based implementation of Kubernetes Container Runtime Interface
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[](https://travis-ci.org/kubernetes-incubator/cri-o)
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[](https://goreportcard.com/report/github.com/kubernetes-incubator/cri-o)
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### Status: pre-alpha
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## What is the scope of this project?
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cri-o is meant to provide an integration path between OCI conformant runtimes and the kubelet.
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Specifically, it implements the Kubelet Container Runtime Interface (CRI) using OCI conformant runtimes.
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The scope of cri-o is tied to the scope of the CRI.
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At a high level, we expect the scope of cri-o to be restricted to the following functionalities:
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* Support multiple image formats including the existing Docker image format
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* Support for multiple means to download images including trust & image verification
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* Container image management (managing image layers, overlay filesystems, etc)
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* Container process lifecycle management
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* Monitoring and logging required to satisfy the CRI
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* Resource isolation as required by the CRI
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## What is not in scope for this project?
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* Building, signing and pushing images to various image storages
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* A CLI utility for interacting with cri-o. Any CLIs built as part of this project are only meant for testing this project and there will be no guarantees on the backwards compatibility with it.
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This is an implementation of the Kubernetes Container Runtime Interface (CRI) that will allow Kubernetes to directly launch and manage Open Container Initiative (OCI) containers.
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The plan is to use OCI projects and best of breed libraries for different aspects:
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- Runtime: [runc](https://github.com/opencontainers/runc) (or any OCI runtime-spec implementation) and [oci runtime tools](https://github.com/opencontainers/runtime-tools)
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- Images: Image management using [containers/image](https://github.com/containers/image)
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- Storage: Storage and management of image layers using [containers/storage](https://github.com/containers/storage)
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- Networking: Networking support through use of [CNI](https://github.com/containernetworking/cni)
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It is currently in active development in the Kubernetes community through the [design proposal](https://github.com/kubernetes/kubernetes/pull/26788). Questions and issues should be raised in the Kubernetes [sig-node Slack channel](https://kubernetes.slack.com/archives/sig-node).
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## Getting started
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### Prerequisites
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`runc` version 1.0.0.rc1 or greater is expected to be installed on the system. It is picked up as the default runtime by ocid.
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### Build
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On Fedora/Centos/RHEL:
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```bash
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dnf install -y btrfs-progs-devel device-mapper-devel libseccomp-devel glib2-devel glibc-devel glibc-static gpgme-devel libassuan-devel libgpg-error-devel pkgconfig libselinux-devel
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```
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On Ubuntu/Debian:
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```bash
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apt install btrfs-tools libassuan-dev libc6-dev libdevmapper-dev libglib2.0-dev libgpg-error-dev libgpgme11-dev pkg-config libseccomp-dev libapparmor-dev
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```
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```bash
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$ export GOPATH=~/go
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$ mkdir $GOPATH
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$ go get -d github.com/kubernetes-incubator/cri-o
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$ cd $GOPATH/src/github.com/kubernetes-incubator/cri-o
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$ make install.tools
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$ make
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$ sudo make install
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```
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Otherwise, if you do not want to build `cri-o` with seccomp support you can add `BUILDTAGS=""` when running make.
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```bash
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# create a 'github.com/kubernetes-incubator' in your $GOPATH/src
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cd github.com/kubernetes-incubator
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git clone https://github.com/kubernetes-incubator/cri-o
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cd cri-o
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make BUILDTAGS=""
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sudo make install
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```
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#### Build Tags
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`cri-o` supports optional build tags for compiling support of various features.
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To add build tags to the make option the `BUILDTAGS` variable must be set.
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```bash
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make BUILDTAGS='seccomp apparmor'
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```
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| Build Tag | Feature | Dependency |
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|-----------|------------------------------------|-------------|
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| seccomp | syscall filtering | libseccomp |
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| selinux | selinux process and mount labeling | <none> |
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| apparmor | apparmor profile support | libapparmor |
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### Running pods and containers
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Follow this [tutorial](tutorial.md) to get started with CRI-O.
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### Setup CNI networking
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A proper description of setting up CNI networking is given in the
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[`contrib/cni` README](contrib/cni/README.md). But the gist is that you need to
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have some basic network configurations enabled and CNI plugins installed on
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your system.
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### Running with kubernetes
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You can run the local version of kubernetes using `local-up-cluster.sh`. After starting `ocid` daemon:
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```sh
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EXPERIMENTAL_CRI=true CONTAINER_RUNTIME=remote CONTAINER_RUNTIME_ENDPOINT='/var/run/ocid.sock --runtime-request-timeout=15m' ./hack/local-up-cluster.sh
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```
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For running on kubernetes cluster - see the [instruction](kubernetes.md)
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### Current Roadmap
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1. Basic pod/container lifecycle, basic image pull (already works)
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1. Support for tty handling and state management
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1. Basic integration with kubelet once client side changes are ready
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1. Support for log management, networking integration using CNI, pluggable image/storage management
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1. Support for exec/attach
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1. Target fully automated kubernetes testing without failures
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