Kubernetes

I do lot of Kubernetes related work either on minikube or local OpenShift cluster setup in a VM. Often I need to create a PersistentVolumeClaim a.k.a. pvc. But to use pvc you have to have a PersistentVolume or pv defined. Enter into the machine running k8s If using minikube you can do minikube ssh Create a local directory for storage mkdir /tmp/pv0001 chmod 777 /tmp/pv0001 If you are on a machine that has SELinux enabled do the following ...

Like many Saturday mornings, Red Hat Bangalore office was once again abuzz with enthusiasm on 8th of April, for hosting yet another successful chapter of Bangalore Kubernetes Meetup. The Meetup had a good turnaround of about 40 people who gave up on their early morning saturday sleep to attend it despite the sweltering hot season and in line were four awesome talks. Suraj Deshmukh set the stage with his opening talk, Kubernetes on CRI-O, wherein he explained different jargons like OCI, CRI, etc., introduced CRI-O and it’s architecture. Explaining how it glues Kubernetes and OCI compliant runtimes and concluding it with a demo showing how Kubernetes uses CRI-O. Link to slides, video. ...

Here is a single node Kubernetes on CRI-O. This setup is done on Fedora 25. Installing OS dependencies dnf -y install \ go \ git \ btrfs-progs-devel \ device-mapper-devel \ glib2-devel \ glibc-devel \ glibc-static \ gpgme-devel \ libassuan-devel \ libgpg-error-devel \ libseccomp-devel \ libselinux-devel \ pkgconfig \ wget \ etcd \ iptables Creating go environment cd ~ mkdir -p ~/go export GOPATH=~/go export GOBIN=$GOPATH/bin export PATH=$PATH:$GOBIN echo 'GOPATH=~/go' >> ~/.bashrc echo 'GOBIN=$GOPATH/bin' >> ~/.bashrc echo 'PATH=$PATH:$GOBIN' >> ~/.bashrc Pull all the code dependencies go get -d k8s.io/kubernetes go get -u github.com/cloudflare/cfssl/cmd/... Install runc go get -d github.com/opencontainers/runc cd $GOPATH/src/github.com/opencontainers/runc git reset --hard v1.0.0-rc3 make BUILDTAGS='seccomp selinux' && make install Build cri-o cd go get -d github.com/kubernetes-incubator/cri-o cd $GOPATH/src/github.com/kubernetes-incubator/cri-o make install.tools make && make install make install.config Set up CNI go get -d github.com/containernetworking/cni cd $GOPATH/src/github.com/containernetworking/cni ./build.sh mkdir -p /opt/cni/bin cp bin/* /opt/cni/bin/ mkdir -p /etc/cni/net.d/ cat > /etc/cni/net.d/10-ocid-bridge.conf <<EOF { "cniVersion": "0.2.0", "name": "ocid-bridge", "type": "bridge", "bridge": "cni0", "isGateway": true, "ipMasq": true, "ipam": { "type": "host-local", "subnet": "10.88.0.0/16", "routes": [ { "dst": "0.0.0.0/0" } ] } } EOF cat > /etc/cni/net.d/99-loopback.conf <<EOF { "cniVersion": "0.2.0", "type": "loopback" } EOF Create policy.json mkdir -p /etc/containers cat > /etc/containers/policy.json <<EOF { "default": [ { "type": "insecureAcceptAnything" } ] } EOF Make SELinux happy mkdir -p /var/lib/containers/ chcon -Rt svirt_sandbox_file_t /var/lib/containers/ Start ocid service export PATH=$PATH:/usr/local/bin/ echo 'PATH=$PATH:/usr/local/bin/' >> ~/.bashrc ocid --runtime /usr/local/sbin/runc --log /root/ocid.log --debug --selinux true Start k8s cluster with crio cd $GOPATH/src/k8s.io/kubernetes/ CONTAINER_RUNTIME=remote CONTAINER_RUNTIME_ENDPOINT='/var/run/ocid.sock --runtime-request-timeout=15m' ./hack/local-up-cluster.sh To use kubectl (in new terminal) ...