Kubernetes v1.6
stable
To run containers in Pods, Kubernetes uses a container runtime. Here are the installation instruction for various runtimes.
Caution:A flaw was found in the way runc handled system file descriptors when running containers. A malicious container could use this flaw to overwrite contents of the runc binary and consequently run arbitrary commands on the container host system.
Please refer to this link for more information about this issue cve-2019-5736 : runc vulnerability
Note: This document is written for users installing CRI onto Linux. For other operating systems, look for documentation specific to your platform.
You should execute all the commands in this guide as root
. For example, prefix commands
with sudo
, or become root
and run the commands as that user.
When systemd is chosen as the init system for a Linux distribution, the init process generates
and consumes a root control group (cgroup
) and acts as a cgroup manager. Systemd has a tight
integration with cgroups and will allocate cgroups per process. It’s possible to configure your
container runtime and the kubelet to use cgroupfs
. Using cgroupfs
alongside systemd means
that there will then be two different cgroup managers.
Control groups are used to constrain resources that are allocated to processes.
A single cgroup manager will simplify the view of what resources are being allocated
and will by default have a more consistent view of the available and in-use resources. When we have
two managers we end up with two views of those resources. We have seen cases in the field
where nodes that are configured to use cgroupfs
for the kubelet and Docker, and systemd
for the rest of the processes running on the node becomes unstable under resource pressure.
Changing the settings such that your container runtime and kubelet use systemd
as the cgroup driver
stabilized the system. Please note the native.cgroupdriver=systemd
option in the Docker setup below.
On each of your machines, install Docker. Version 18.06.2 is recommended, but 1.11, 1.12, 1.13, 17.03 and 18.09 are known to work as well. Keep track of the latest verified Docker version in the Kubernetes release notes.
Use the following commands to install Docker on your system:
# Install Docker CE
## Set up the repository:
### Update the apt package index
apt-get update
### Install packages to allow apt to use a repository over HTTPS
apt-get update && apt-get install apt-transport-https ca-certificates curl software-properties-common
### Add Docker’s official GPG key
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -
### Add docker apt repository.
add-apt-repository \
"deb [arch=amd64] https://download.docker.com/linux/ubuntu \
$(lsb_release -cs) \
stable"
## Install docker ce.
apt-get update && apt-get install docker-ce=18.06.2~ce~3-0~ubuntu
# Setup daemon.
cat > /etc/docker/daemon.json <<EOF
{
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2"
}
EOF
mkdir -p /etc/systemd/system/docker.service.d
# Restart docker.
systemctl daemon-reload
systemctl restart docker
# Install Docker CE
## Set up the repository
### Install required packages.
yum install yum-utils device-mapper-persistent-data lvm2
### Add docker repository.
yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo
## Install docker ce.
yum update && yum install docker-ce-18.06.2.ce
## Create /etc/docker directory.
mkdir /etc/docker
# Setup daemon.
cat > /etc/docker/daemon.json <<EOF
{
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2",
"storage-opts": [
"overlay2.override_kernel_check=true"
]
}
EOF
mkdir -p /etc/systemd/system/docker.service.d
# Restart docker.
systemctl daemon-reload
systemctl restart docker
Refer to the official Docker installation guides for more information.
This section contains the necessary steps to install CRI-O
as CRI runtime.
Use the following commands to install CRI-O on your system:
modprobe overlay
modprobe br_netfilter
# Setup required sysctl params, these persist across reboots.
cat > /etc/sysctl.d/99-kubernetes-cri.conf <<EOF
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF
sysctl --system
# Install prerequisites
apt-get update
apt-get install software-properties-common
add-apt-repository ppa:projectatomic/ppa
apt-get update
# Install CRI-O
apt-get install cri-o-1.11
# Install prerequisites
yum-config-manager --add-repo=https://cbs.centos.org/repos/paas7-crio-311-candidate/x86_64/os/
# Install CRI-O
yum install --nogpgcheck cri-o
systemctl start crio
Refer to the CRI-O installation guide for more information.
This section contains the necessary steps to use containerd
as CRI runtime.
Use the following commands to install Containerd on your system:
modprobe overlay
modprobe br_netfilter
# Setup required sysctl params, these persist across reboots.
cat > /etc/sysctl.d/99-kubernetes-cri.conf <<EOF
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF
sysctl --system
Containerd releases are published regularly, the values below are hardcoded to the latest version available at the time of writing. Please check for newer versions and hashes here.
# Export required environment variables.
export CONTAINERD_VERSION="1.1.2"
export CONTAINERD_SHA256="d4ed54891e90a5d1a45e3e96464e2e8a4770cd380c21285ef5c9895c40549218"
# Download containerd tar.
wget https://storage.googleapis.com/cri-containerd-release/cri-containerd-${CONTAINERD_VERSION}.linux-amd64.tar.gz
# Check hash.
echo "${CONTAINERD_SHA256} cri-containerd-${CONTAINERD_VERSION}.linux-amd64.tar.gz" | sha256sum --check -
# Unpack.
tar --no-overwrite-dir -C / -xzf cri-containerd-${CONTAINERD_VERSION}.linux-amd64.tar.gz
# Start containerd.
systemctl start containerd
Refer to the Frakti QuickStart guide for more information.
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