# Images As of Kubernetes 1.18 the default images used by kOps are the **[official Ubuntu 20.04](#ubuntu-2004-focal)** images. You can choose a different image for an instance group by editing it with `kops edit ig nodes`. You should see an `image` field in one of the following formats: * `ami-abcdef` - specifies an AMI by id directly * `/` specifies an AMI by its owner's account ID and name properties * `/` specifies an AMI by its [owner's alias](#owner-aliases) and name properties Using the AMI id is precise, but ids vary by region. It is often more convenient to use the `/` if equivalent images with the same name have been copied to other regions. ```yaml 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 ``` You can find the name for an image using: `aws ec2 describe-images --region us-east-1 --image-id ami-00579fbb15b954340` ## Security Updates Automated security updates are handled by kOps for Debian, Flatcar and Ubuntu distros. This can be disabled by editing the cluster configuration: ```yaml 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](#amazon-linux-2) | 1.10 | 1.18 | - | - | | [CentOS 7](#centos-7) | - | 1.5 | - | - | | [CentOS 8](#centos-8) | 1.15 | - | - | - | | [CoreOS](#coreos) | 1.6 | 1.9 | 1.17 | 1.18 | | [Debian 8](#debian-8-jessie) | - | 1.5 | 1.17 | 1.18 | | [Debian 9](#debian-9-stretch) | 1.8 | 1.10 | - | - | | [Debian 10](#debian-10-buster) | 1.13 | 1.17 | - | - | | [Flatcar](#flatcar) | 1.15.1 | 1.17 | - | - | | [Kope.io](#kopeio) | - | - | 1.18 | - | | [RHEL 7](#rhel-7) | - | 1.5 | - | - | | [RHEL 8](#rhel-8) | 1.15 | 1.18 | - | - | | [Ubuntu 16.04](#ubuntu-1604-xenial) | 1.5 | 1.10 | 1.17 | 1.20 | | [Ubuntu 18.04](#ubuntu-1804-bionic) | 1.10 | 1.16 | - | - | | [Ubuntu 20.04](#ubuntu-2004-focal) | 1.16.2 | 1.18 | - | - | ## Supported Distros ### Amazon Linux 2 Amazon Linux 2 is based on Kernel version **4.14** which fixes some of the bugs present in RHEL/CentOS 7 and effects are less visible, but it's still quite old. 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: ```bash 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-hvm-2*-x86_64-gp2" ``` ### CentOS 7 CentOS 7 is based on Kernel version **3.10** which has a considerable number of known bugs that affect it and may be noticed in production clusters: * [kubernetes/kubernetes#56903](https://github.com/kubernetes/kubernetes/issues/56903) * [kubernetes/kubernetes#67577](https://github.com/kubernetes/kubernetes/issues/67577) The minimum supported version is **7.4**. Available images can be listed using: ```bash aws ec2 describe-images --region us-east-1 --output table \ --owners 125523088429 \ --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \ --filters "Name=name,Values=CentOS 7.*x86_64" ``` ### CentOS 8 CentOS 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: ```bash aws ec2 describe-images --region us-east-1 --output table \ --owners 125523088429 \ --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \ --filters "Name=name,Values=CentOS 8.*x86_64" ``` ### Debian 9 (Stretch) Debian 9 is based on Kernel version **4.9** which has a number of known bugs that affect it and which may be noticed with larger clusters: This release is **EOL**, which means that the Debian Security Team no longer handles security fixes. That is now the responsibility/purview of the LTS team, which is a group of volunteers who are paid by donations to Debian LTS. * [kubernetes/kubernetes#56903](https://github.com/kubernetes/kubernetes/issues/56903) * [kubernetes/kubernetes#67577](https://github.com/kubernetes/kubernetes/issues/67577) Available images can be listed using: ```bash aws ec2 describe-images --region us-east-1 --output table \ --owners 379101102735 \ --query "sort_by(Images, &CreationDate)[*].[CreationDate,Name,ImageId]" \ --filters "Name=name,Values=debian-stretch-hvm-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](https://youtu.be/KHMnC3kj3Js?t=771) than the legacy version. It is recommended to switch to `iptables` legacy by using the following script in `additionalUserData` for each instance group: ```yaml 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: ```bash 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-*" ``` ### Flatcar Flatcar is a friendly fork of CoreOS and as such, compatible with it. Available images can be listed using: ```bash 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 7 RHEL 7 is based on Kernel version **3.10** which has a considerable number of known bugs that affect it and may be noticed in production clusters: * [kubernetes/kubernetes#56903](https://github.com/kubernetes/kubernetes/issues/56903) * [kubernetes/kubernetes#67577](https://github.com/kubernetes/kubernetes/issues/67577) The minimum supported version is **7.4**. Available images can be listed using: ```bash 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-7.*x86_64*" ``` ### 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: ```bash 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*" ``` ### Ubuntu 18.04 (Bionic) Ubuntu 18.04 is based on Kernel version **4.15** which has a number of known bugs that affect it and which may be noticed with larger clusters: * [kubernetes/kubernetes#56903](https://github.com/kubernetes/kubernetes/issues/56903) * [kubernetes/kubernetes#67577](https://github.com/kubernetes/kubernetes/issues/67577) Available images can be listed using: ```bash 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-*" ``` ### 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: ```bash 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-*" ``` ## Deprecated Distros ### CoreOS Support for CoreOS was removed in kOps 1.18. You should consider using [Flatcar](#flatcar) as a replacement. ### Debian 8 (Jessie) Support for Debian 8 (Jessie) was removed in kOps 1.18. ### Kope.io Support for _kope.io_ images is deprecated. These images were the default until Kubernetes 1.18, when they were replaced by the [official Ubuntu 20.04](#ubuntu-2004-focal) images. The _kope.io_ images were based on [Debian 9 (Stretch)](#debian-9-stretch) and had all packages required by kOps pre-installed. Other than that, the changes to the official Debian images were [minimal](https://github.com/kubernetes-sigs/image-builder/blob/master/images/kube-deploy/imagebuilder/templates/1.18-stretch.yml#L174-L198). ### Ubuntu 16.04 (Xenial) Support for Ubuntu 16.04 (Xenial) is deprecated and will be removed in kOps 1.20. ## Owner aliases kOps supports owner aliases for the official accounts of supported distros: * `kope.io` => `383156758163` * `amazon` => `137112412989` * `centos` => `125523088429` * `debian9` => `379101102735` * `debian10` => `136693071363` * `flatcar` => `075585003325` * `redhat` => `309956199498` * `ubuntu` => `099720109477`