Data Domain: Upgrade precheck found one blocking issue. DD trusts CA with incorrect version (4). 

Symptom: During upgrade precheck an error: Current Upgrade Status: DD OS precheck found 1 blocking issue.

Example:

sysadmin@dd9300# system upgrade status
Current Upgrade Status: DD OS precheck found 1 blocking issue(s)
Node   Severity   Issue                           Solution
----   --------   ------------------------------  --------
0      WARNING    The default                     Local user passwords may
                  password-strength policy        need to be modified to
                  will be updated after the       comply with new policy.
                  upgrade.
0      CRITICAL   DD trusts CA with incorrect     Retry upgrade after
                  version (4).                    Regenerating the CA with
                                                  subject <systemhostname>
0      WARNING    1 precheck script(s) failed     Please get more details in
                  to complete                     /ddr/var/log/debug/platform/in
                                                  fra.log
End time: 2023.06.21:12:47

1. Look at the trusts on the DD. 

•     #adminaccess trust show
•     Look for the corresponding hostname from the error from the precheck.

Example:    

sysadmin@dd9300# adminaccess trust show
Subject                 Type         Valid From                 Valid Until                Fingerprint
---------------------   ----------   ------------------------   ------------------------   -----------------------------------------------------------
<systemHostname>        trusted-ca   Thu Mar 24 10:33:03 2011   Sun Mar 16 10:33:03 2042   6F:22:F5:ED:F6:F2:29:82:2A:17:CE:6A:31:9D:2A:E2:60:2B:69:81
ddmc                    trusted-ca   Sun Aug 24 10:22:40 2014   Wed Aug 16 10:22:40 2045   1B:CC:CC:44:04:ED:21:B9:69:D2:7C:96:31:C7:DE:BC:15:CC:04:AB
dpc                     trusted-ca   Tue Nov 12 20:30:53 2019   Tue Nov 13 20:30:53 2029   A1:57:6A:10:B8:1E:88:72:01:88:61:F1:7D:D4:BC:22:4D:14:73:36
dd9300                  trusted-ca   Wed Oct  7 11:37:39 2020   Tue Oct  6 11:37:39 2026   54:A8:64:D1:FA:60:3C:81:42:89:D5:DD:78:D1:2B:74:AF:E6:F5:04
dd9300                  trusted-ca   Wed Oct  7 11:46:36 2020   Tue Oct  6 11:46:36 2026   DE:C2:6B:CC:BA:7A:EE:14:11:8E:76:CC:9A:23:A7:C4:8E:0D:6F:53
---------------------   ----------   ------------------------   ------------------------   -----------------------------------------------------------

2. Verify with the customer if they are still using the DD system corresponding to the hostname in error. It is common that the system is no longer in use. It could be used for DDMC monitoring as well. You can also confirm with a command if it is being used for replication:

•     #replication show config 
•     This checks whether the DD is using the hostname for mtree replication, if the hostname is in use you have to regenerate the certificate. 
•      In this example, the DD is no longer in use and not found in the replication config.

        
Example: 

sysadmin@dd9300# replication show  config
CTX   Source                                                  Destination                                             Connection                          Low-bw-optim   Crepl-gc-bw-optim   Encryption    Enabled   Max-repl-
                                                                                                                      Host and Port                                                          (Auth-mode)             streams
---   -----------------------------------------------------   -----------------------------------------------------   ---------------------------------   ------------   -----------------   -----------   -------   ---------
1     mtree://dd9300/data/col1/DD9300                          mtree://9300/data/col1/DD9300   dd9300.xxxx.org         (default)                             disabled       disabled            disabled      yes       32
---   -----------------------------------------------------   -----------------------------------------------------   ---------------------------------   ------------   

3. If confirmed that the trust is not needed for replication or DDMC, remove the old trust:

•     # adminaccess trust del host <hostname of other DD>
•     Example: # adminaccess trust del host <systemHostname>

        
4. Try to rerun the precheck and it should be successful.