This tutorial will walk you through the installation of cri-o, an Open Container Initiative-based implementation of Kubernetes Container Runtime Interface, and the creation of Redis server running in a Pod.
A Linux machine is required to download and build the cri-o components and run the commands in this tutorial.
Create a machine running Ubuntu 16.10:
gcloud compute instances create cri-o \
--machine-type n1-standard-2 \
--image-family ubuntu-1610 \
--image-project ubuntu-os-cloud
SSH into the machine:
gcloud compute ssh cri-o
This section will walk you through installing the following components:
- ocid - The implementation of the Kubernetes CRI, which manages Pods.
- ocic - The ocid client for testing.
- cni - The Container Network Interface
- runc - The OCI runtime to launch the container
- docker - Temporary dependency for pulling and storing docker images on disk.
Download the runc release binary:
wget https://github.com/opencontainers/runc/releases/download/v1.0.0-rc2/runc-linux-amd64
Set the executable bit and copy the runc binary into your PATH:
chmod +x runc-linux-amd64
sudo mv runc-linux-amd64 /usr/bin/runc
Print the runc version:
runc -version
runc version 1.0.0-rc2
commit: c91b5bea4830a57eac7882d7455d59518cdf70ec
spec: 1.0.0-rc2-dev
The ocid project does not ship binary releases so you'll need to build it from source.
Download the Go 1.7.4 binary release:
wget https://storage.googleapis.com/golang/go1.7.4.linux-amd64.tar.gz
Install Go 1.7.4:
sudo tar -xvf go1.7.4.linux-amd64.tar.gz -C /usr/local/
mkdir -p $HOME/go/src
export GOPATH=$HOME/go
export PATH=$PATH:/usr/local/go/bin:$GOPATH/bin
At this point the Go 1.7.4 tool chain should be installed:
go version
go version go1.7.4 linux/amd64
sudo apt-get install -y libglib2.0-dev libseccomp-dev libapparmor-dev
go get -d github.com/kubernetes-incubator/cri-o
cd $GOPATH/src/github.com/kubernetes-incubator/cri-o
make install.tools
make
sudo make install
Output:
install -D -m 755 kpod /usr/bin/kpod
install -D -m 755 ocid /usr/bin/ocid
install -D -m 755 ocic /usr/bin/ocic
install -D -m 755 conmon/conmon /usr/libexec/ocid/conmon
install -D -m 755 pause/pause /usr/libexec/ocid/pause
install -d -m 755 /usr/share/man/man{1,5,8}
install -m 644 docs/kpod.1 docs/kpod-launch.1 -t /usr/share/man/man1
install -m 644 docs/ocid.conf.5 -t /usr/share/man/man5
install -m 644 docs/ocid.8 -t /usr/share/man/man8
install -D -m 644 ocid.conf /etc/ocid/ocid.conf
install -D -m 644 seccomp.json /etc/ocid/seccomp.json
sudo sh -c 'echo "[Unit]
Description=OCI-based implementation of Kubernetes Container Runtime Interface
Documentation=https://github.com/kubernetes-incubator/cri-o
[Service]
ExecStart=/usr/bin/ocid --debug
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target" > /etc/systemd/system/ocid.service'
sudo systemctl daemon-reload
sudo systemctl enable ocid
sudo systemctl start ocid
sudo ocic runtimeversion
VersionResponse: Version: 0.1.0, RuntimeName: runc, RuntimeVersion: 1.0.0-rc2, RuntimeApiVersion: v1alpha1
This tutorial will use the latest version of cni from the master branch and build it from source.
Download the cni source tree:
go get -d github.com/containernetworking/cni
cd $GOPATH/src/github.com/containernetworking/cni
Build the cni binaries:
./build
Output:
Building API
Building reference CLI
Building plugins
flannel
tuning
bridge
ipvlan
loopback
macvlan
ptp
dhcp
host-local
noop
Install the cni binaries:
sudo mkdir -p /opt/cni/bin
sudo cp bin/* /opt/cni/bin/
sudo mkdir -p /etc/cni/net.d
sudo sh -c 'cat >/etc/cni/net.d/10-mynet.conf <<-EOF
{
"cniVersion": "0.2.0",
"name": "mynet",
"type": "bridge",
"bridge": "cni0",
"isGateway": true,
"ipMasq": true,
"ipam": {
"type": "host-local",
"subnet": "10.88.0.0/16",
"routes": [
{ "dst": "0.0.0.0/0" }
]
}
}
EOF'
sudo sh -c 'cat >/etc/cni/net.d/99-loopback.conf <<-EOF
{
"cniVersion": "0.2.0",
"type": "loopback"
}
EOF'
At this point cni is installed and configured to allocation IP address to containers from the 10.88.0.0/16 subnet.
Docker is required to pull and store docker images on the local filesystem. The dependency on the docker daemon will go away over time as cri-o will eventually support these features natively.
Download the Docker 1.12.4 binary release:
wget https://get.docker.com/builds/Linux/x86_64/docker-1.12.4.tgz
Extract and install the Docker binaries:
tar -xvf docker-1.12.4.tgz
sudo cp docker/docker* /usr/bin/
sudo sh -c 'echo "[Unit]
Description=Docker Application Container Engine
Documentation=http://docs.docker.io
[Service]
ExecStart=/usr/bin/docker daemon \
--iptables=false \
--ip-masq=false \
--host=unix:///var/run/docker.sock \
--log-level=error \
--storage-driver=overlay
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target" > /etc/systemd/system/docker.service'
sudo systemctl daemon-reload
sudo systemctl enable docker
sudo systemctl start docker
sudo docker version
Output:
Client:
Version: 1.12.4
API version: 1.24
Go version: go1.6.4
Git commit: 1564f02
Built: Tue Dec 13 02:47:26 2016
OS/Arch: linux/amd64
Server:
Version: 1.12.4
API version: 1.24
Go version: go1.6.4
Git commit: 1564f02
Built: Tue Dec 13 02:47:26 2016
OS/Arch: linux/amd64
Now that the cri-o components have been installed and configured we are ready to create a Pod. This section will walk you through lauching a Redis server in a Pod. Once the Redis server is running we'll use telnet to verify it's working, then we'll stop the Redis server and clean up the Pod.
First we need to setup a Pod sandbox using a Pod configuration, which can be found in the cri-o source tree:
cd $GOPATH/src/github.com/kubernetes-incubator/cri-o
Next create the Pod and capture the Pod ID for later use:
POD_ID=$(sudo ocic pod create --config test/testdata/sandbox_config.json)
sudo ocic pod create --config test/testdata/sandbox_config.json
Use the ocic command to get the status of the Pod:
sudo ocic pod status --id $POD_ID
Output:
ID: cd6c0883663c6f4f99697aaa15af8219e351e03696bd866bc3ac055ef289702a
Name: podsandbox1
UID: redhat-test-ocid
Namespace: redhat.test.ocid
Attempt: 1
Status: SANDBOX_READY
Created: 2016-12-14 15:59:04.373680832 +0000 UTC
Network namespace: /var/run/netns/cni-bc37b858-fb4d-41e6-58b0-9905d0ba23f8
IP Address: 10.88.0.2
Labels:
group -> test
Annotations:
owner -> hmeng
security.alpha.kubernetes.io/seccomp/pod -> unconfined
security.alpha.kubernetes.io/sysctls -> kernel.shm_rmid_forced=1,net.ipv4.ip_local_port_range=1024 65000
security.alpha.kubernetes.io/unsafe-sysctls -> kernel.msgmax=8192
Use the ocic command to create a redis container from a container configuration and attach it to the Pod created earlier:
CONTAINER_ID=$(sudo ocic ctr create --pod $POD_ID --config test/testdata/container_redis.json)
sudo ocic ctr create --pod $POD_ID --config test/testdata/container_redis.json
The ocic ctr create command will take a few seconds to return because the redis container needs to be pulled using the docker daemon.
Start the Redis container:
sudo ocic ctr start --id $CONTAINER_ID
Get the status for the Redis container:
sudo ocic ctr status --id $CONTAINER_ID
Output:
ID: d0147eb67968d81aaddbccc46cf1030211774b5280fad35bce2fdb0a507a2e7a
Name: podsandbox1-redis
Status: CONTAINER_RUNNING
Created: 2016-12-14 16:00:42.889089352 +0000 UTC
Started: 2016-12-14 16:01:56.733704267 +0000 UTC
Connect to the Pod IP on port 6379:
telnet 10.88.0.2 6379
Trying 10.88.0.2...
Connected to 10.88.0.2.
Escape character is '^]'.
At the prompt type MONITOR:
Trying 10.88.0.2...
Connected to 10.88.0.2.
Escape character is '^]'.
MONITOR
+OK
Exit the telnet session by typing ctrl-] and quit at the prompt:
^]
telnet> quit
Connection closed.
The Redis logs are logged to the stderr of the ocid service, which can be viewed using journalctl:
sudo journalctl -u ocid --no-pager
sudo ocic ctr stop --id $CONTAINER_ID
sudo ocic ctr remove --id $CONTAINER_ID
sudo ocic pod stop --id $POD_ID
sudo ocic pod remove --id $POD_ID
sudo ocic pod list
sudo ocic ctr list