Choosing an upgrade strategy
There are two ways to upgrade Plesk. The choice between one or the other depends on the server environment (the OS, installed third-party software, and system resources):
In-place upgrade is preformed using Parallels Installer on the same server. This strategy can be used if the OS installed on the server is supported by the target Plesk version and has not been discontinued under the terms of the Plesk Lifecycle Policy. However, if the server has hosting software that is not supported by the target Plesk version (for example, hMailServer, MDaemon, or Gene6 FTP Server), it is strongly recommended to do an upgrade by transfer.
Upgrade by transfer is the process of switching to the latest Plesk version by moving all of the hosting data and settings from the current Plesk server to a server with the latest version of Parallels Plesk Panel installed. This strategy is preferred when upgrading servers with an OS that either falls under the end-of-life policy or is approaching the support termination date. Upgrade by transfer also allows you to minimize downtime of services on the production server, as websites stay online while the transfer is in progress.
This guide will help you to perform an in-place upgrade of Plesk. If upgrade by transfer is your preferred method, check our migration and transfer best practices guides:
- Parallels Plesk Panel for Windows: Migration Best Practices and Usecases
- Parallels Plesk Panel for Linux: Migration Best Practices and Usecases
Before we begin...
Before starting the upgrade, let's go through a short checklist to verify that an upgrade is possible and viable and make sure that the server has enough resources and satisfies all prerequisites:
Make sure that the OS running on the server is still supported by the vendor and is not approaching its termination date (check the Parallels Plesk Panel Lifecycle Policy page). If the OS is close to its end of life, it is recommended to upgrade by transfer: set up the new server with a modern OS and the latest version of Plesk and use Parallels Plesk Migration & Transfer Manager to copy data from the old server.
Read the release notes and verify that the server satisfies the target version's software requirements and that all software installed on the server is compatible with the target version. For example, if a server has hMailServer installed and set up as a mail server in Plesk, then upgrading to Plesk 11.0.9 or 11.5 may be unsuccessful, as these versions do not support hMailServer. In such cases, an upgrade by transfer is strongly recommended.
Check that the current version of Plesk supports upgrading to the target version. This information can be found in the "Earlier Versions Supported for Upgrade" section of the Plesk Release Notes.
Check that there are at least 4 gigabytes of free disk space on the server in each of the following directories:
- On Windows:
- On Linux:
/opt/psaon Debian and Ubuntu)
- On Windows:
On Linux, verify that the system package manager (Yum on CentOS and RHEL, APT on Debian and Ubuntu) is properly configured and can fetch and install packages from the OS vendor's repositories.
On Windows, determine which database provider is used to store the Plesk configuration database (article #3453). If the Plesk database provider is Jet, switch it to MySQL using the instructions provided in the article #5532. It will save time during the upgrade.
Download and run the latest pre-upgrade checker (KB article #9436). Check all warnings returned by the script. If a problem is found, it is reported as a warning in the final report. The log file will have a full description of the issue with a link to a helpful KB article. Apply the solutions, then re-run the pre-upgrade checker until no warnings are reported or only non-critical issues (such as business logic warnings) are left.
Read the sections "Notes on Installation, Upgrade, and Migration" and "Known Problems and Limitations" in the release notes of the target Plesk version and take the necessary actions.
Plan the upgrade. Choose a time-frame when the server load is the lowest and the service downtime impact on hosting customers is minimal.
Now that all checks have been successfully passed, it is time to start the upgrade.
Note: If Plesk is installed in a container using Parallels Virtuozzo Containers templates, consider performing an upgrade using templates. See full list of instructions in the article #117518.
If you are running Plesk 10.4.4, go to Tools & Settings > Updates and Upgrades and begin the upgrade using Parallels Installer's web interface. Otherwise, download the latest Autoinstaller for your OS and architecture from our website and run it:
chmod +x ./parallels_installer_v3.12.0_build120601.16_os_CentOS_6 ./parallels_installer_v3.12.0_build120601.16_os_CentOS_6_x86_64 --web-interface
If an upgrade on Linux has been started while connected to the server via SSH, make sure that the connection is not interrupted before the upgrade process finishes. The best practice is to use the screen console screen manager, which allows multiple console sessions over a single SSH connection and keeps programs running in virtual terminals, even if the SSH connection is interrupted. You can get acquainted with this handy tool through this short introduction manual.
On Windows, a persistent connection is not a concern, as Windows preserves applications and keeps them running, even after a remote desktop session is disconnected.
IMPORTANT! When the upgrade process is running, do not interrupt Parallels Installer or reboot the server.
If something goes wrong ...
If there is no output from Parallels Installer for a long time, it does not mean that the upgrade has stuck. Instead, some silent background operation might be taking a long time to run. Check what is happening on the server:
On Linux, run "
ps axfww" and check the process tree that stems from the Parallels Installer process. See if any of these processes are running ("R" state). Run the command several times with an interval of 1-3 minutes and check if there is any change.
On Windows, download Process Explorer from Microsoft Technet, unpack it, and run it. Check the process tree and see if any child processes of
ai.exeare consuming CPU or opening/closing files.
If the upgrade fails, check for error messages in the output, as well as in the log files (
c:\ParallelsInstaller\autoinstaller3.logon Windows or
/tmp/plesk_11.0.9_installation.logon Linux). Look up found messages in Parallels Knowledgebase for solutions.
To continue a failed upgrade, re-run
ai.exeon Windows or use the following command on Linux:
- Installation, Upgrade, Migration, and Transfer Guide
- Parallels Plesk Panel 11.0 Release Notes:
- Parallels Plesk Panel 11.5 Release Notes