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Images

As of Kubernetes 1.18 the default images used by kOps are the official Ubuntu 20.04 images.

You can choose a different image for an instance group by editing it with kops edit ig nodes.

For AWS, you should set the image field in one of the following formats: * ami-abcdef - specifies an image by id directly (image id is precise, but ids vary by region) * <owner>/<name> specifies an image by its owner's account ID and name properties * <alias>/<name> specifies an image by its owner's alias and name properties * ssm:<ssm_parameter> specifies an image through an SSM parameter (kOps 1.25.3+)

image: ami-00579fbb15b954340
image: 099720109477/ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-20200423
image: ubuntu/ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-20200423
image: ssm:/aws/service/canonical/ubuntu/server/20.04/stable/current/amd64/hvm/ebs-gp2/ami-id

Security Updates

Automated security updates are handled by kOps for Debian, Flatcar and Ubuntu distros. This can be disabled by editing the cluster configuration:

spec:
  updatePolicy: external

Distros Support Matrix

The following table provides the support status for various distros with regards to kOps version:

Distro Experimental Stable Deprecated Removed
Amazon Linux 2 1.10 1.18 - -
CentOS 7 - 1.5 1.21 1.23
CentOS 8 1.15 - 1.21 1.23
CoreOS 1.6 1.9 1.17 1.18
Debian 8 - 1.5 1.17 1.18
Debian 9 1.8 1.10 1.21 1.23
Debian 10 1.13 1.17 - -
Debian 11 1.21.1 - - -
Flatcar 1.15.1 1.17 - -
Kope.io - - 1.18 1.23
RHEL 7 - 1.5 1.21 1.23
RHEL 8 1.15 1.18 - -
Rocky 8 1.23.2 1.24 - -
Ubuntu 16.04 1.5 1.10 1.17 1.20
Ubuntu 18.04 1.10 1.16 1.26 -
Ubuntu 20.04 1.16.2 1.18 - -
Ubuntu 22.04 1.23 1.24 - -

Supported Distros

Amazon Linux 2

Amazon Linux 2 has variants using Kernel versions 4.14 and 5.10. Be sure to use the 5.10 images as specified in the image filter below. More information is available in the AWS Documentation.

For kOps versions 1.16 and 1.17, the only supported Docker version is 18.06.3. Newer versions of Docker cannot be installed due to missing dependencies for container-selinux. This issue is fixed in kOps 1.18.

Available images can be listed using:

aws ec2 describe-images --region us-east-1 --output table \
  --owners 137112412989 \
  --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \
  --filters "Name=name,Values=amzn2-ami-kernel-5.10-hvm-2*-x86_64-gp2"

Debian 10 (Buster)

Debian 10 is based on Kernel version 4.19 which fixes some of the bugs present in Debian 9 and effects are less visible.

One notable change is the addition of iptables NFT, which is by default. This is not yet supported by most CNI plugins and seems to be slower than the legacy version. It is recommended to switch to iptables legacy by using the following script in additionalUserData for each instance group:

additionalUserData:
  - name: busterfix.sh
    type: text/x-shellscript
    content: |
      #!/bin/sh
      update-alternatives --set iptables /usr/sbin/iptables-legacy
      update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy
      update-alternatives --set arptables /usr/sbin/arptables-legacy
      update-alternatives --set ebtables /usr/sbin/ebtables-legacy

Available images can be listed using:

# Amazon Web Services (AWS)
aws ec2 describe-images --region us-east-1 --output table \
  --owners 136693071363 \
  --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \
  --filters "Name=name,Values=debian-10-amd64-*"

# Google Cloud Platform (GCP)
gcloud compute images list --filter debian-10-buster-v

# Microsoft Azure
az vm image list --all --output table \
  --publisher Debian --offer debian-10 --sku 10-gen2

Debian 11 (Bullseye)

Debian 11 is based on Kernel version 5.10 which has no known major Kernel bugs and fully supports all Cilium features.

Available images can be listed using:

# Amazon Web Services (AWS)
aws ec2 describe-images --region us-east-1 --output table \
  --owners 136693071363 \
  --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \
  --filters "Name=name,Values=debian-11-amd64-*"

# Google Cloud Platform (GCP)
gcloud compute images list --filter debian-11-bullseye-v

# Microsoft Azure
az vm image list --all --output table \
  --publisher Debian --offer debian-11 --sku 11-gen2

Flatcar

Flatcar is a friendly fork of CoreOS and as such, compatible with it.

Available images can be listed using:

aws ec2 describe-images --region us-east-1 --output table \
  --owners 075585003325 \
  --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \
  --filters "Name=name,Values=Flatcar-stable-*-hvm"

RHEL 8

RHEL 8 is based on Kernel version 4.18 which fixes some of the bugs present in RHEL/CentOS 7 and effects are less visible.

One notable change is the addition of iptables NFT, which is the only iptables backend available. This may not be supported by some CNI plugins and should be used with care.

Available images can be listed using:

aws ec2 describe-images --region us-east-1 --output table \
  --owners 309956199498 \
  --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \
  --filters "Name=name,Values=RHEL-8.*x86_64*"

Rocky 8

Rocky Linux is a community enterprise Operating System designed to be 100% bug-for-bug compatible with RHEL 8.

Available images can be listed using:

aws ec2 describe-images --region us-east-1 --output table \
  --owners 792107900819 \
  --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \
  --filters "Name=name,Values=Rocky-8-ec2-8.*.x86_64"

Ubuntu 20.04 (Focal)

Ubuntu 20.04 is based on Kernel version 5.4 which fixes all the known major Kernel bugs.

Available images can be listed using:

# Amazon Web Services (AWS)
aws ec2 describe-images --region us-east-1 --output table \
  --owners 099720109477 \
  --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \
  --filters "Name=name,Values=ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-*"

# Google Cloud Platform (GCP)
gcloud compute images list --filter ubuntu-2004-focal-v

# Microsoft Azure
az vm image list --all --output table \
  --publisher Canonical --offer 0001-com-ubuntu-server-focal --sku 20_04-lts-gen2

Ubuntu 22.04 (Jammy)

Ubuntu 22.04 is based on Kernel version 5.15 which fixes all the known major Kernel bugs.

Available images can be listed using:

# Amazon Web Services (AWS)
aws ec2 describe-images --region us-east-1 --output table \
  --owners 099720109477 \
  --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \
  --filters "Name=name,Values=ubuntu/images/hvm-ssd/ubuntu-jammy-22.04-amd64-*"

# Google Cloud Platform (GCP)
gcloud compute images list --filter ubuntu-2204-jammy-v

# Microsoft Azure
az vm image list --all --output table \
  --publisher Canonical --offer 0001-com-ubuntu-server-jammy --sku 22_04-lts-gen2

Deprecated Distros

Ubuntu 18.04 (Bionic)

Ubuntu 18.04.5 is based on Kernel version 5.4 which fixes all the known major Kernel bugs. Earlier patch versions may still work, but are not recommended nor supported.

Available images can be listed using:

aws ec2 describe-images --region us-east-1 --output table \
  --owners 099720109477 \
  --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \
  --filters "Name=name,Values=ubuntu/images/hvm-ssd/ubuntu-bionic-18.04-amd64-*"

Owner aliases

kOps supports owner aliases for the official accounts of supported distros:

  • amazon => 137112412989
  • debian10 => 136693071363
  • debian11 => 136693071363
  • flatcar => 075585003325
  • redhat => 309956199498
  • ubuntu => 099720109477