• /var/lib/pulp is shared from Pulp 2 machine

  • access to Pulp 2 database

  • [recommended] all Pulp 3 supported checksum types are allowed


The migration workload is very I/O intensive. It’s highly recommended that the volume backing your Postgresql database be on a SSD or other low latency, high IOPS storage volume.


On Pulp 2 machine

1. Make sure MongoDB listens on the IP address accesible outside, it should be configured as one of the bindIP in /etc/mongod.conf.

  1. Make sure /var/lib/pulp is on a shared filesystem.


If you experience Pulp 2 workers timing out during the migration, consider making them more tolerant to delayed mongodb writes by increasing the worker_timeout setting in the [tasks] section of your Pulp 2 server.conf. Typically a value of 300 seconds has worked well even during large migration workloads.

On Pulp 3 machine

  1. Mount /var/lib/pulp to your Pulp 3 storage location. By default, it’s /var/lib/pulp.

2. Configure your connection to MongoDB in your settings, /etc/pulp/ You can use the same configuration as you have in Pulp 2 (only seeds might need to be different, it depends on your setup). By default it’s configured to connect to localhost:27017.


    'name': 'pulp_database',
    'seeds': '<your MongoDB bindIP>:27017',
    'username': '',
    'password': '',
    'replica_set': '',
    'ssl': False,
    'ssl_keyfile': '',
    'ssl_certfile': '',
    'verify_ssl': True,
    'ca_path': '/etc/pki/tls/certs/ca-bundle.crt',

3. Configure ALLOWED_CONTENT_CHECKSUMS in your settings, /etc/pulp/ before you run a migration. It is recommended to list all Pulp 3 supported checksum types. pulp-2to3-migration is shipped with such default configuration. In case you have a custom one in /etc/pulp/, make sure it lists all types as shown below:

ALLOWED_CONTENT_CHECKSUMS = ['md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512']

If you are sure that your Pulp 2 installation has no md5 or sha1 checksums for any content (on_demand or downloaded) or in any distributor configuration, then you are fine to exclude those from the setting.

If you are concerned having md5 and sha1 enabled, you can always adjust the setting after the migration is done and remove those two checksum types from the allowed list. After modifying the setting, you likely will need to run pulpcore-manager handle-artifact-checksums to remove unsupported checksums from the database, or Pulp will refuse to start.


If you’d like to run Pulp 3 on a machine where FIPS is enabled, you will need to patch Django and Pulp at your own risk The patches will go away when Django project starts supporting FIPS mode (see for details). Recommendations for the ALLOWED_CONTENT_CHECKSUMS configuration are the same as for the non-FIPS mode.

4. Configure CONTENT_PREMIGRATION_BATCH_SIZE if needed. If your Pulp 2 setup is large and your system is relatively slow in terms of I/O (e.g. you have HDD), consider adjusting the batch size for content premigration. The default is 1000.

It is recommended to decrease it gradually, approximately by half each time. On a very slow system and with many errata content to migrate, it might need to go as low as 50. Decreasing the value increases the time of content migration from pulp 2 to pulp 3. It’s noticeable for a large setups only.

The main sign that CONTENT_PREMIGRATION_BATCH_SIZE needs to go down is the pymongo.errors.CursorNotFound: Cursor not found errors in logs.

In addition you may also configure DEB_COMPONENT_BATCH_SIZE which starts with a default of 50. Since each deb_component creates a large number of Pulp2to3Content during pre_migration, it is appropriate to set a significantly lower batch size, as compared to other types! You can identify CursorNotFound errors, caused by deb_component migration, by checking if the backtrace passes through the pulp_2to3_migration/app/plugin/deb/ file.


If you experience Pulp 3 workers timing out during the migration, consider making them more tolerant to delayed PostgreSQL writes by increasing the Pulp 3 WORKER_TTL setting. Typically a value of 300 seconds has worked well even during large migration workloads. This setting is available in pulpcore>=3.11.