[root@sc2kubm40 ~]# yum install -y epel-release
<strong>Singularity and git related components can then be installed</strong>
[root@sc2kubm40 ~]# yum install -y singularity-runtime singularity git socat golang gcc libseccomp-devel
<strong>Since the Singularity CRI is in beta, it needs to be downloaded with git and compiled. These steps can be avoided once it becomes generally available.</strong>
[root@sc2kubm40 ~]# git clone https://github.com/sylabs/singularity-cri.git
Cloning into ‘singularity-cri’...
remote: Enumerating objects: 396, done.
remote: Counting objects: 100% (396/396), done.
remote: Compressing objects: 100% (312/312), done.
remote: Total 7523 (delta 115), reused 337 (delta 66), pack–reused 7127
Receiving objects: 100% (7523/7523), 7.59 MiB | 3.18 MiB/s, done.
Resolving deltas: 100% (3573/3573), done.
[root@sc2kubm40 ~]# cd singularity-cri
[root@sc2kubm40 singularity–cri]# git checkout tags/v1.0.0-beta.6 -b v1.0.0-beta.6
Switched to a new branch ‘v1.0.0-beta.6’
[root@sc2kubm40 singularity–cri]# make
GO bin/sycri
[root@sc2kubm40 singularity–cri]# make install
INSTALL /usr/local/bin/sycri
INSTALL /usr/local/etc/sycri/sycri.yaml
<strong>A systemd startup script for Singularity CRI should be created as shown below or using your favorite editor.</strong>
[root@sc2kubm40 singularity–cri]# cat <<EOF > /etc/systemd/system/sycri.service
> [Unit]
> Description=Singularity–CRI
> After=network.target
>
> [Service]
> Type=simple
> Restart=always
> RestartSec=1
> ExecStart=/usr/local/bin/sycri
> Environment=“PATH=/usr/local/libexec/singularity/bin:/bin:/sbin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin”
>
> [Install]
> WantedBy=multi–user.target
> EOF
<strong>Once the service has been created, it has to be enabled to startup automatically on boot and started.</strong>
[root@sc2kubm40 singularity–cri]# systemctl enable sycri
Created symlink from /etc/systemd/system/multi–user.target.wants/sycri.service to /etc/systemd/system/sycri.service.
[root@sc2kubm40 singularity–cri]# systemctl start sycri
<strong>SELINUX and swap should be disabled as shown below.</strong>
# Disable SELinux
[root@sc2kubm40 singularity–cri]# setenforce 0
[root@sc2kubm40 singularity–cri]# sed -i –follow-symlinks ‘s/SELINUX=enforcing/SELINUX=disabled/g’ /etc/sysconfig/selinux
# Disable swap
[root@sc2kubm40 singularity–cri]# swapoff -a
[root@sc2kubm40 singularity–cri]# sed -e ‘/swap/s/^/#/g’ -i /etc/fstab
<strong>Verify the Singularity runtime is running and is listening on a TCP socket as shown below.</strong>
[root@sc2kubm40 singularity–cri]# ls -l /var/run/singularity.sock
srw——- 1 root root 0 Oct 30 11:12 /var/run/singularity.sock
<strong>The Kubelet configuration should be edited to make it use the singularity runtime instead of the default docker runtime as shown below.</strong>
[root@sc2kubm40 ~]# cat /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS=–container–runtime=remote
—container–runtime–endpoint=unix:///var/run/singularity.sock
—image–service–endpoint=unix:///var/run/singularity.sock
<strong>The Kubelet service has to be stopped and started to activate the changes.</strong>
[root@sc2kubm40 singularity–cri]# systemctl stop kubelet
[root@sc2kubm40 singularity–cri]# systemctl start kubelet
<strong>Initialize kubeadm with the singularity run time as shown below.</strong>
[root@sc2kubm40 singularity–cri]# kubeadm init –pod-network-cidr=192.168.0.0/16 –cri-socket unix:///var/run/singularity.sock
I1030 11:17:10.162386 27725 version.go:240] remote version is much newer: v1.16.2; falling back to: stable–1.14
[init] Using Kubernetes version: v1.14.3
[preflight] Running pre–flight checks
[WARNING Firewalld]: firewalld is active, please ensure ports [6443 10250] are open or your cluster may not function correctly
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using ‘kubeadm config images pull’
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