Pulp

The first time you try to sync using Pulp 3 that was installed on the same machine as Pulp 2 you get the following error in the Task:

{
    "_created": "2019-07-17T19:18:30.230257Z",
    "_href": "/pulp/api/v3/tasks/be5b916a-2c50-4558-9057-d538beb0daed/",
    "created_resources": [],
    "error": {
        "code": null,
        "description": "[Errno 13] Permission denied: '/var/lib/pulp/artifact'",
    ...

The permissions on /var/lib/pulp set by Pulp 2 don't allow group members to write to that directory.

$ ls -la /var/lib/pulp/
total 8
drwxr-xr-x.  6 apache  pulp    132 Jul 17 18:26 .
drwxr-xr-x. 39 root    root   4096 Jul 17 18:28 ..
-rw-r--r--.  1 apache  apache    2 Jul 17 18:16 0005_puppet_module_name_change.txt
-rw-r--r--.  1 root    root      0 Jul 17 18:16 db_initialized.flag
drwxr-xr-x.  7 apache  pulp     73 Jul 17 18:16 published
drwxr-xr-x.  2 apache  pulp     25 Jul 17 18:16 static
drwxrwxr-x.  5 vagrant pulp    269 Jul 17 18:28 tmp
drwxr-xr-x.  2 apache  pulp      6 Jul  3 17:53 uploads

pulp-server RPM for Pulp 2 needs to set the change the permissions on /var/lib/pulp to 775.

This was fixed in 2.20.1, but the change was omitted from 2.21.0.