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--- litespeed_wiki:cloudlinux:lsphp_criu_enable [2018/05/11 12:14]
Eric Leu [How to Verify]
+++ litespeed_wiki:cloudlinux:lsphp_criu_enable [2019/10/15 18:40]
Lisa Clarke [How to Enable CRIU on CloudLinux + cPanel EA4 + LSWS]
@@ Line 1: / Line 1: @@
-====== How to enable CRIU ======
+====== Enabling CRIU on CloudLinux + cPanel EA4 + LSWS ======
-===== Summary =====
+**IMPORTANT!! CRIU may cause stability issues! Enable CRIU AT YOUR OWN RISK!**
-Checkpoint/Restore In Userspace, or CRIU, is an open source project which dumps all of the information of a running process to disk and restores it at the point of the dump.  The Litespeed Enterprise Edition Web Server now supports CRIU both natively, and for the CloudLinux/Apache specific implementation for the PHP processor.  This will improve the performance of Litespeed for transactions which are commonly used and reduce the memory overhead on the server.
+Checkpoint/Restore In Userspace, or CRIU, is an open source project which dumps all of the information of a running process to disk and restores it at the point of the dump.  The LiteSpeed Enterprise Edition Web Server now supports CRIU for the CloudLinux implementation of the PHP processor.
-===== Must =====
+However, generally, we don't recommend you enable CRIU unless you have a special requirement for it. CRIU uses significant server resources and may generate unusual errors while providing no performance benefits.
-  - Running as the root user to use CRIU Litespeed or Apache. The CRIU facility requires Litespeed run as the root user to perform the snapshot and recovery. Running as a non-root user automatically disables CRIU.
+**We have received quite a few reports that potential bugs on the CRIU module may cause web server stability issues. Please permanently disable CRIU, or enable CRIU AT YOUR OWN RISK**.
-  - CloudLinux System
+===== Requirements =====
+  - CloudLinux System
+  - ea-apache24-mod_lsapi 1.1 on cpanel EA4 (or mod_lsapi on cPanel EA3)  or above
+  - LiteSpeed Web Server 5.3 or above.
 ===== Installation =====
-==== 1. CRIU enabled from System ====
-Login your Linux system. Check CRIU service is running or not. \\
+==== Verify CRIU is enabled on your system ====
-If not, enable by following method \\
+Criu is installed with dependency to ea-apache24-mod_lsapi for cpanel EA4( or mod_lsapi for cpanel EA3) 1.1 and above package.
+If you have not installed it, you should:
+<code>yum install liblsapi liblsapi-devel</code>
+<code>
+=============================================================================================================================================================================
+ Package                                Arch                          Version                                        Repository                                         Size
+=============================================================================================================================================================================
+Installing:
+ liblsapi                               x86_64                        1.1-28.el7.cloudlinux                          cloudlinux-x86_64-server-7                        180 k
+ liblsapi-devel                         x86_64                        1.1-28.el7.cloudlinux                          cloudlinux-x86_64-server-7                         37 k
+Installing for dependencies:
+ crit-lve                               x86_64                        3.7-3.el7                                      cloudlinux-x86_64-server-7                        9.6 k
+ criu-lve                               x86_64                        3.7-3.el7                                      cloudlinux-x86_64-server-7                        439 k
+ criu-lve-devel                         x86_64                        3.7-3.el7                                      cloudlinux-x86_64-server-7                         11 k
+ libnet                                 x86_64                        1.1.6-7.el7                                    cloudlinux-x86_64-server-7                         58 k
+ protobuf-c                             x86_64                        1.0.2-3.el7                                    cloudlinux-x86_64-server-7                         27 k
+ protobuf-python                        x86_64                        2.5.0-8.el7                                    cloudlinux-x86_64-server-7                        129 k
+ python-criu-lve                        x86_64                        3.7-3.el7                                      cloudlinux-x86_64-server-7                        136 k
+ python-ipaddr                          noarch                        2.1.11-1.el7                                   cloudlinux-x86_64-server-7                         34 k
+Transaction Summary
+=============================================================================================================================================================================
+Install  2 Packages (+8 Dependent packages)
+</code>
+<code>yum install ea-apache24-mod_lsapi</code>
+Check CRIU whether the service is running or not. \\
+  ps -ef | grep criu
+  root      967641       1  0 19:24 ?        00:00:00 /usr/sbin/criu service -v4 -o /var/log/criu-service.log --address /var/run/criu/criu_service.socket
+  root      967680  965818  0 19:24 pts/1    00:00:00 grep --color=auto criu
+If not, enable by following method:
 <code>
 systemctl enable criu
 systemctl start criu
 systemctl status criu
 </code>
-Output **''Active: active (running)''**
-====2. CRIU parameter check====
-Generally PHP should be compiled with criu already.   \\
-Through ''phpinfo()'' to check LSPHP build with parameter: ''-DWITH_CRIU''.
-If you want to manually compile, please download LSAPI from [[https://www.litespeedtech.com/open-source/litespeed-sapi/download | here ]]
+Output should be ''Active: active (running)''.
-====3. php env config====
+  [root@globalsupport ~]# systemctl status criu
-Add following necessary parameter to the PHPx.x External App -> Environment \\
+  ● criu.service - Checkpoint Restore in Userspace daemon
+   Loaded: loaded (/usr/lib/systemd/system/criu.service; disabled; vendor preset: disabled)
+   Active: active (running) since Mon 2018-08-20 19:24:25 UTC; 4min 23s ago
+  Process: 967640 ExecStartPre=/bin/mkdir -p /var/run/criu (code=exited, status=0/SUCCESS)
+  Main PID: 967641 (criu)
+   CGroup: /system.slice/criu.service
+           └─967641 /usr/sbin/criu service -v4 -o /var/log/criu-service.log --address /var/run/criu/criu_service.socket
+  Aug 20 19:24:25 globalsupport.litespeedtech.com systemd[1]: Starting Checkpoint Restore in Userspace daemon...
+  Aug 20 19:24:25 globalsupport.litespeedtech.com systemd[1]: Started Checkpoint Restore in Userspace daemon.
+  Aug 20 19:24:25 globalsupport.litespeedtech.com criu[967641]: Warn  (criu/kerndat.c:660): Can't load /run/criu.kdat
+====CRIU Master Switch on LSWS ====
+CRIU is disabled by default. To enable it, you can go to LSWS Web Admin Console -> Server -> PHP -> PHP Global Configuration -> Enable CRIU( Again, we recommend you keep CRIU off unless you have some speical testing need only).
+{{:litespeed_wiki:cloudlinux:lsws-master-criu-switch.png?800|}}
+==== Check CRIU parameters====
+In CloudLinux, LSPHP have been compiled with CRIU already. Please check [[https://docs.cloudlinux.com/index.html?criu_support.html|here]]   \\
+Use ''phpinfo()'' with parameter ''-DWITH_CRIU'' to check the LSPHP build.
+====Configure the PHP environment====
+Add the following necessary parameter to the PHPx.x **External App > Environment** \\
 <code>
 LSAPI_CRIU=1
@@ Line 35: / Line 99: @@
 {{:litespeed_wiki:cloudlinux:criu-2.png?|}}
-====Important Syntax====
+===Important Syntax===
 ^Variable^Values^Default^Description^
 |LSAPI_CRIU|1/On/Off|Off|If set to On, CRIU will be performed. 1=On|
@@ Line 43: / Line 107: @@
 ===== How to Verify =====
-**Step 1** \\
+====Step 1====
-  - Prepare any php site, e.g. WordPress
+  - Prepare any PHP site, e.g. WordPress
+====Step 2====
-**Step 2** \\
   - Generate the dump by hitting the WordPress site
   - Hit more than INITIAL_START number, e.g. 20 times
-  - If image dump generated, you should see an image folder under ''/var/run/lsws/cl_criu/''
+  - If an image dump is generated, you should see an image folder under ''/var/run/lsws/cl_criu/''
-**Step 3** \\
+====Step 3====
-  - Check PHP process number by \\ ''ps -ef | grep php'' \\ ''>>> user      868577  ...   10:54   0:00 lsphp''
+  - Check the PHP process number by <code>ps -ef | grep php
-  - Kill the lsphp process \\ ''kill -9  868577''
+>>> user      868577  ...   10:54   0:00 lsphpL</code>
-**Step 4** \\
+  - Kill the lsphp process via <code>kill -9  868577</code>
-  - To restore the PHP by refreshing the WordPress page to regenerate it
+====Step 4====
-  - Verify the process number is same as before \\ ''ps -ef | grep php'' \\ ''>>> user      868577  ...   10:55   0:00 lsphp'' \\ Process is **back**!!
+  - Restore the PHP by refreshing the WordPress page to regenerate it
-  - You can also check standard error log \\ ''LSCRIU: Successful CloudLinux dump of PID: 868577'' \\ ''LSCRIU: Successful CloudLinux restore of PID: 868577, parent: 1.''
+  - Verify the process number is the same as before:<code>ps -ef | grep php
+>>> user      868577  ...   10:55   0:00 lsphp</code>The process is **back**!!
+  - You can also check standard error log for something like <code>LSCRIU: Successful CloudLinux dump of PID: 868577
+LSCRIU: Successful CloudLinux restore of PID: 868577, parent: 1.</code>
 ===== Logs =====
-  - **Error log** default locate at Apache standard error log
+  - **Error log** default located at Apache standard error log
-  - **dump.log** is in the images directory
+  - ''dump.log'' is in the images directory
-  - **restore.log** is in the images directory
+  - ''restore.log'' is in the images directory
-  * restore.log will gets generated even though there is no dump, so it's expected to see some related fail logs
+**NOTE**: ''restore.log'' is generated even when there is no dump, so it's expected to see some related fail logs