Drop support for RHEL 7 / CentOS 7 (kubernetes-sigs#11246)

* Simplify docker systemd unit

systemd handles missing unit by ignoring the dependency so we don't need
to template them.

* Remove RHEL 7/CentOS 7 support

- remove ref in kubespray roles
- move CI from centos 7 to 8
- remove docs related to centos7

* Remove container-storage-setup

Only used for RHEL 7 and CentOS 7

Author: VannTen

README.md

@@ -143,11 +143,11 @@ vagrant up
 - **Flatcar Container Linux by Kinvolk**
 - **Debian** Bookworm, Bullseye
 - **Ubuntu** 20.04, 22.04, 24.04
-- **CentOS/RHEL** 7, [8, 9](docs/operating_systems/centos.md#centos-8)
+- **CentOS/RHEL** [8, 9](docs/operating_systems/centos.md#centos-8)
 - **Fedora** 37, 38
 - **Fedora CoreOS** (see [fcos Note](docs/operating_systems/fcos.md))
 - **openSUSE** Leap 15.x/Tumbleweed
-- **Oracle Linux** 7, [8, 9](docs/operating_systems/centos.md#centos-8)
+- **Oracle Linux** [8, 9](docs/operating_systems/centos.md#centos-8)
 - **Alma Linux** [8, 9](docs/operating_systems/centos.md#centos-8)
 - **Rocky Linux** [8, 9](docs/operating_systems/centos.md#centos-8)
 - **Kylin Linux Advanced Server V10** (experimental: see [kylin linux notes](docs/operating_systems/kylinlinux.md))

Vagrantfile

@@ -22,8 +22,6 @@ SUPPORTED_OS = {
   "ubuntu2004"          => {box: "generic/ubuntu2004",         user: "vagrant"},
   "ubuntu2204"          => {box: "generic/ubuntu2204",         user: "vagrant"},
   "ubuntu2404"          => {box: "bento/ubuntu-24.04",         user: "vagrant"},
-  "centos"              => {box: "centos/7",                   user: "vagrant"},
-  "centos-bento"        => {box: "bento/centos-7.6",           user: "vagrant"},
   "centos8"             => {box: "centos/8",                   user: "vagrant"},
   "centos8-bento"       => {box: "bento/centos-8",             user: "vagrant"},
   "almalinux8"          => {box: "almalinux/8",                user: "vagrant"},
@@ -36,7 +34,6 @@ SUPPORTED_OS = {
   "opensuse-tumbleweed" => {box: "opensuse/Tumbleweed.x86_64", user: "vagrant"},
   "oraclelinux"         => {box: "generic/oracle7",            user: "vagrant"},
   "oraclelinux8"        => {box: "generic/oracle8",            user: "vagrant"},
-  "rhel7"               => {box: "generic/rhel7",              user: "vagrant"},
   "rhel8"               => {box: "generic/rhel8",              user: "vagrant"},
   "debian11"            => {box: "debian/bullseye64",          user: "vagrant"},
   "debian12"            => {box: "debian/bookworm64",          user: "vagrant"},

contrib/dind/group_vars/all/distro.yaml

@@ -18,7 +18,7 @@ distro_settings:
     init: |
       /sbin/init
   centos: &CENTOS
-    image: "centos:7"
+    image: "centos:8"
     user: "centos"
     pid1_exe: /usr/lib/systemd/systemd
     init: |

docs/CNI/calico.md

@@ -424,7 +424,7 @@ calico_wireguard_enabled: true
 
 The following OSes will require enabling the EPEL repo in order to bring in wireguard tools:
 
-* CentOS 7 & 8
+* CentOS 8
 * AlmaLinux 8
 * Rocky Linux 8
 * Amazon Linux 2

docs/CRI/docker.md

@@ -16,14 +16,6 @@ Enabling the `overlay2` graph driver:
 docker_storage_options: -s overlay2
 ```
 
-Enabling `docker_container_storage_setup`, it will configure devicemapper driver on Centos7 or RedHat7.
-Deployers must be define a disk path for `docker_container_storage_setup_devs`, otherwise docker-storage-setup will be executed incorrectly.
-
-```yaml
-docker_container_storage_setup: true
-docker_container_storage_setup_devs: /dev/vdb
-```
-
 Changing the Docker cgroup driver (native.cgroupdriver); valid options are `systemd` or `cgroupfs`, default is `systemd`:
 
 ```yaml

docs/developers/ci.md

@@ -8,7 +8,7 @@ To generate this Matrix run `./tests/scripts/md-table/main.py`
 |---| --- | --- | --- | --- | --- | --- | --- | --- |
 almalinux8 |  :white_check_mark: | :x: | :x: | :x: | :white_check_mark: | :x: | :x: | :x: |
 amazon |  :white_check_mark: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
-centos7 |  :white_check_mark: | :x: | :x: | :white_check_mark: | :x: | :white_check_mark: | :x: | :white_check_mark: |
+centos8 |  :white_check_mark: | :x: | :x: | :white_check_mark: | :x: | :white_check_mark: | :x: | :white_check_mark: |
 debian11 |  :white_check_mark: | :x: | :white_check_mark: | :x: | :x: | :x: | :white_check_mark: | :x: |
 debian12 |  :white_check_mark: | :white_check_mark: | :white_check_mark: | :x: | :x: | :x: | :x: | :x: |
 fedora37 |  :white_check_mark: | :x: | :x: | :x: | :x: | :white_check_mark: | :x: | :x: |
@@ -26,7 +26,7 @@ ubuntu24 |  :white_check_mark: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 |---| --- | --- | --- | --- | --- | --- | --- | --- |
 almalinux8 |  :white_check_mark: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 amazon |  :x: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
-centos7 |  :x: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
+centos8 |  :x: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 debian11 |  :x: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 debian12 |  :x: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 fedora37 |  :white_check_mark: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
@@ -44,7 +44,7 @@ ubuntu24 |  :x: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 |---| --- | --- | --- | --- | --- | --- | --- | --- |
 almalinux8 |  :white_check_mark: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 amazon |  :x: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
-centos7 |  :white_check_mark: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
+centos8 |  :white_check_mark: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 debian11 |  :white_check_mark: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 debian12 |  :white_check_mark: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |
 fedora37 |  :x: | :x: | :x: | :x: | :x: | :x: | :x: | :x: |

docs/developers/vagrant.md

@@ -80,7 +80,7 @@ cat << EOF > vagrant/config.rb
 \$instance_name_prefix = "kub"
 \$vm_cpus = 1
 \$num_instances = 3
-\$os = "centos-bento"
+\$os = "centos8-bento"
 \$subnet = "10.0.20"
 \$network_plugin = "flannel"
 \$inventory = "$INV"

docs/operating_systems/centos.md

@@ -1,10 +1,5 @@
 # CentOS and derivatives
 
-## CentOS 7
-
-The maximum python version officially supported in CentOS is 3.6. Ansible as of version 5 (ansible core 2.12.x) increased their python requirement to python 3.8 and above.
-Kubespray supports multiple ansible versions but only the default (5.x) gets wide testing coverage. If your deployment host is CentOS 7 it is recommended to use one of the earlier versions still supported.
-
 ## CentOS 8
 
 If you have containers that are using iptables in the host network namespace (`hostNetwork=true`),

inventory/sample/group_vars/all/offline.yml

@@ -82,7 +82,7 @@
 # krew_download_url: "{{ files_repo }}/github.com/kubernetes-sigs/krew/releases/download/{{ krew_version }}/krew-{{ host_os }}_{{ image_arch }}.tar.gz"
 
 ## CentOS/Redhat/AlmaLinux
-### For EL7, base and extras repo must be available, for EL8, baseos and appstream
+### For EL8, baseos and appstream must be available,
 ### By default we enable those repo automatically
 # rhel_enable_repos: false
 ### Docker / Containerd

playbooks/ansible_version.yml

@@ -25,7 +25,6 @@
       tags:
         - check
 
-    # CentOS 7 provides too old jinja version
     - name: "Check that jinja is not too old (install via pip)"
       assert:
         msg: "Your Jinja version is too old, install via pip"