Merge pull request #312 from rtulchii/cgroup-v2-support-docs

Cgroup v2 support docs

Author: annkots

docs/cloudlinuxos/cloudlinux_os_kernel/README.md

@@ -554,12 +554,12 @@ The following profiles are provided by CloudLinux OS:
 - cloudlinux-default              - CloudLinux hosting profile (DEPRECATED)
 - cloudlinux-default-base         - Base CloudLinux hosting profile
 - cloudlinux-default-cgv1         - Optimized CloudLinux hosting Servers with cgroups v1
-- cloudlinux-default-cgv2         - Optimized CloudLinux hosting Servers with cgroups v2 (NOT SUPPORTED YET)
+- cloudlinux-default-cgv2         - Optimized CloudLinux hosting Servers with cgroups v2
 - cloudlinux-dummy                - Empty CloudLinux tuned profile
 - cloudlinux-latency-performance  - CloudLinux latency-performance profile (DEPRECATED)
 - cloudlinux-latency-performance-base  - Base CloudLinux latency-performance profile
 - cloudlinux-latency-performance-cgv1  - Optimized CloudLinux hosting Servers with cgroups v1
-- cloudlinux-latency-performance-cgv2  - Optimized CloudLinux hosting Servers with cgroups v2 (NOT SUPPORTED YET)
+- cloudlinux-latency-performance-cgv2  - Optimized CloudLinux hosting Servers with cgroups v2
 - cloudlinux-vz                   - Empty CloudLinux tuned profile
 ```
 </div>
@@ -570,7 +570,7 @@ The recommended profile for most servers is **<span class="notranslate">cloudlin
 The profiles are organized in a hierarchy:
 - **<span class="notranslate">cloudlinux-default-base</span>** / **<span class="notranslate">cloudlinux-latency-performance-base</span>** — contain all generic tuning parameters (sysctl, CPU governor, OOM adjustments). Not intended for direct use.
 - **<span class="notranslate">cloudlinux-default-cgv1</span>** / **<span class="notranslate">cloudlinux-latency-performance-cgv1</span>** — include the base profile and add cgroups v1 boot parameters. **Recommended for most servers.**
-- **<span class="notranslate">cloudlinux-default-cgv2</span>** / **<span class="notranslate">cloudlinux-latency-performance-cgv2</span>** — reserved for future cgroups v2 support. Not supported yet.
+- **<span class="notranslate">cloudlinux-default-cgv2</span>** / **<span class="notranslate">cloudlinux-latency-performance-cgv2</span>** — include the base profile and add cgroups v2 boot parameters. Supported starting from **kmod-lve 2.1-58** on **CloudLinux OS 8, 9, 10, and Ubuntu 22**.
 - **<span class="notranslate">cloudlinux-default</span>** / **<span class="notranslate">cloudlinux-latency-performance</span>** — **deprecated** wrappers that internally include the <span class="notranslate">-cgv1</span> variants. They remain functional for backward compatibility (e.g. existing Ansible scripts), but new installations should use the <span class="notranslate">-cgv1</span> profiles directly.
 
 When upgrading from older versions, the deprecated profiles are automatically switched to their <span class="notranslate">-cgv1</span> equivalents.
@@ -664,6 +664,68 @@ tuned-adm off
 ```
 </div>
 
+### Switching between cgroup v1 and cgroup v2
+
+CloudLinux OS supports **cgroup v2** on **CloudLinux OS 8, 9, 10, and Ubuntu 22** — CloudLinux OS 7 is not supported.
+
+::: tip Note
+**CloudLinux OS 10** uses **cgroup v2 by default**. On **CloudLinux OS 8, 9, and Ubuntu 22**, cgroup v1 is the default.
+:::
+
+The following package versions are required:
+
+| Package | CL8 | CL9 | CL10 | Ubuntu 22 |
+|---------|-----|-----|------|-----------|
+| `kmod-lve` / `kmodlve-dkms` | 2.1-58+ | 2.1-58+ | 2.1-58+ | 2.1-58+ |
+| `tuned-profiles-cloudlinux` | 0.2-14+ | 0.2-15+ | 0.3-6+ | 0.2-10+ |
+
+To switch between cgroup versions, apply the appropriate tuned profile and reboot the server. Choose the profile that matches your current profile family (`cloudlinux-default` or `cloudlinux-latency-performance`).
+
+**Enable cgroup v2 (default profile):**
+<div class="notranslate">
+
+```
+tuned-adm profile cloudlinux-default-cgv2
+reboot
+```
+</div>
+
+**Enable cgroup v2 (latency-performance profile):**
+<div class="notranslate">
+
+```
+tuned-adm profile cloudlinux-latency-performance-cgv2
+reboot
+```
+</div>
+
+**Revert to cgroup v1 (default profile):**
+<div class="notranslate">
+
+```
+tuned-adm profile cloudlinux-default-cgv1
+reboot
+```
+</div>
+
+**Revert to cgroup v1 (latency-performance profile):**
+<div class="notranslate">
+
+```
+tuned-adm profile cloudlinux-latency-performance-cgv1
+reboot
+```
+</div>
+
+To verify that the server has booted with cgroup v2 and that the LVE module is operating correctly, check the kernel log after reboot:
+<div class="notranslate">
+
+```
+dmesg | grep -i "cgroups"
+```
+</div>
+
+The presence of the message **"detected cgroups v2"** in the output confirms that the system is running with cgroup v2.
 
 ## Kernel config variables