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Upgrade from MongoDB Community Edition to Percona Server for MongoDB

This document provides instructions for an in-place upgrade from MongoDB Community Edition to Percona Server for MongoDB.

An in-place upgrade is done by keeping the existing data in the server and replacing the MongoDB binaries. Afterwards, you restart the mongod service with the same dbpath data directory.

An in-place upgrade is suitable for most environments except the ones that use ephemeral storage and/or host addresses.

Procedure

Note

MongoDB creates a user that belongs to two groups, which is a potential security risk. This is fixed in Percona Server for MongoDB: the user is included only in the mongod group. To avoid problems with current MongoDB setups, existing user group membership is not changed when you migrate to Percona Server for MongoDB. Instead, a new mongod user is created during installation, and it belongs to the mongod group.

This procedure describes an in-place upgrade of a mongod instance. If you are using data at rest encryption, refer to the Upgrading to Percona Server for MongoDB with data at rest encryption enabled section.

Important

Before starting the upgrade, we recommend to perform a full backup of your data.

  1. Save the current configuration file as the backup:

    $ sudo mv /etc/mongod.conf /etc/mongod.conf.bkp
    
  2. Stop the mongod service:

    $ sudo systemctl stop mongod
    
  3. Check for installed packages:

    $ sudo dpkg -l | grep mongod
    

    Output:

    ii  mongodb-org                      4.4.15                       amd64        MongoDB open source document-oriented database system (metapackage)
    ii  mongodb-org-database             4.4.15                       amd64        MongoDB open source document-oriented database system (metapackage)
    ii  mongodb-org-database-tools-extra 4.4.15                       amd64        Extra MongoDB database tools
    ii  mongodb-org-mongos               4.4.15                       amd64        MongoDB sharded cluster query router
    ii  mongodb-org-server               4.4.15                       amd64        MongoDB database server
    ii  mongodb-org-shell                4.4.15                       amd64        MongoDB shell client
    ii  mongodb-org-tools                4.4.15                       amd64        MongoDB tools
    
  4. Remove the installed packages:

    $ sudo apt remove \
      mongodb-org \
      mongodb-org-mongos \
      mongodb-org-server \
      mongodb-org-shell \
      mongodb-org-tools
    
  5. Install Percona Server for MongoDB

  6. Verify that the configuration file includes correct options:

    • Copy the required configuration options like custom dbPath/system log path, additional security/replication or sharding options from the backup configuration file (/etc/mongod.conf) to the current one /etc/mongodb.conf.
    • Make sure that the mongod user has access to your custom paths. If not, provide it as follows:

      $ sudo chown -R mongod:mongod <custom-dbPath>
      $ sudo chown -R mongod:mongod <custom-systemLog.path>
      
    • Make sure the configuration file includes the following configuration:

      processManagement:
         fork: true
         pidFilePath: /var/run/mongod.pid
      

      Troubleshooting tip: The pidFilePath setting in mongod.conf must match the PIDFile option in the systemd mongod service unit. Otherwise, the service will kill the mongod process after a timeout.

  7. Restart the mongod service:

    $ sudo systemctl restart mongod
    
  1. Stop the mongod service:

    $ sudo systemctl stop mongod
    
  2. Check for installed packages:

    $ sudo rpm -qa | grep mongo
    

    Output:

    mongodb-org-shell-4.4.15-1.el8.x86_64
    mongodb-org-database-4.4.15-1.el8.x86_64
    mongodb-org-4.4.15-1.el8.x86_64
    mongodb-database-tools-100.4.1-1.x86_64
    mongodb-org-server-4.4.15-1.el8.x86_64
    mongodb-org-mongos-4.4.15-1.el8.x86_64
    mongodb-org-tools-4.4.15-1.el8.x86_64
    
  3. Remove the installed packages:

    $ sudo yum remove \
    mongodb-org-shell-4.4.15-1.el8.x86_64 \
    mongodb-org-database-4.4.15-1.el8.x86_64 \
    mongodb-org-4.4.15-1.el8.x86_64 \
    mongodb-database-tools-100.4.1-1.x86_64 \
    mongodb-org-server-4.4.15-1.el8.x86_64 \
    mongodb-org-mongos-4.4.15-1.el8.x86_64 \
    mongodb-org-tools-4.4.15-1.el8.x86_64
    
  4. Install Percona Server for MongoDB

  5. Verify that the configuration file includes correct options:

    • When you remove old packages, your existing configuration file is saved as /etc/mongod.conf.rpmsave. Copy the required configuration options like custom dbPath/system log path, additional security/replication or sharding options from the backup configuration file (/etc/mongod.conf.rpmsave) to the current one /etc/mongodb.conf.
    • Make sure that the mongod user has access to your custom paths. If not, provide it as follows:

      $ sudo chown -R mongod:mongod <custom-dbPath>
      $ sudo chown -R mongod:mongod <custom-systemLog.path>
      
    • Make sure the configuration file includes the following configuration:

      processManagement:
         fork: true
         pidFilePath: /var/run/mongod.pid
      

      Troubleshooting tip: The pidFilePath setting in mongod.conf must match the PIDFile option in the systemd mongod service unit. Otherwise, the service will kill the mongod process after a timeout.

  6. Restart the mongod service:

    $ sudo systemctl restart mongod
    

To upgrade a replica set or a sharded cluster, use the rolling restart method. It allows you to perform the upgrade with minimum downtime. You upgrade the nodes one by one, while the whole cluster / replica set remains operational.

See also

MongoDB Documentation:

Upgrading to Percona Server for MongoDB with data at rest encryption enabled

Steps to upgrade from MongoDB 4.4 Community Edition with data encryption enabled to Percona Server for MongoDB are different. mongod requires an empty dbPath data directory because it cannot encrypt data files in place. It must receive data from other replica set members during the initial sync. Please refer to the Switching storage engines for more information on migration of encrypted data. Contact us for working at the detailed migration steps, if further assistance is needed.

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