This article explains an issue where the device QFX10002 while upgrading got into amnesiac mode and customer is unable to login to the device and the steps to resolve the problem.

1. Device is inaccessible via ssh.
2. On the console user is able to login only with the root credentials.
3. After the upgrade the device shows in amnesiac mode but unable to login with the configured local credentials.

FreeBSD/i386 (Amnesiac) (ttyu0)

login: Dec 18 06:00:27   snmpd[4297]: SNMPD_SEND_FAILURE: jnx_netsnmp_udp_send: send message (x.x.x.x) failure: No route to host
Dec 18 06:00:30   authd[4289]: LICENSE_SOCKET_FAILURE: 'evConnect' failed for socket 30:


FreeBSD/i386 (Amnesiac) (ttyu0)

login: abc
Dec 18 06:00:34   login: login_getclass: unknown class 'junos-login-defaults'
Password:
Dec 18 06:00:34   login: login_getclass: unknown class 'junos-login-defaults'
Login incorrect

4. On the console logs we may observe the following logs which suggests that the device has some incompatible configuration with 17.x code and hence the configuration was committed partially.

@ 1734501426 [2024-12-18 05:57:06 UTC] mgd start
Creating initial configuration:  ...
mgd: Running FIPS Self-tests
mgd: Veriexec is not enforced, FIPS mode not available
mgd: FIPS Self-tests Skipped
[edit vlans XYZ l3-interface]
  'l3-interface irb.100'
    Interface must already be defined under [edit interfaces]
mgd: error: commit failed: (statements constraint check failed)
Warning: Commit failed, activating partial configuration.
Warning: Edit the router configuration to fix these errors.
@ 1734501435 [2024-12-18 05:57:15 UTC] mgd done

In the above case there are few steps can be taken based on the accessibility of the device.

1. If root credentials work then proceed with removal/deactivation of the incompatible configuration. For example in the above case "deactivate vlan XYZ l3-interface irb.100" and then commit the change. This will load the complete configuration.
2. If the root credentials are not working then proceed with root password recovery and then execute the first step.