Harbor: vmware harbor ui error -- severe

[mramanathan]

$ docker version
Client:
Version: 18.05.0-ce
API version: 1.37
Go version: go1.9.5
Git commit: f150324
Built: Wed May 9 22:14:54 2018
OS/Arch: linux/amd64
Experimental: false
Orchestrator: swarm

Server:
Engine:
Version: 18.05.0-ce
API version: 1.37 (minimum version 1.12)
Go version: go1.9.5
Git commit: f150324
Built: Wed May 9 22:18:36 2018
OS/Arch: linux/amd64
Experimental: false

$ /usr/local/bin/docker-compose version
docker-compose version 1.21.2, build a133471
docker-py version: 3.3.0
CPython version: 3.6.5
OpenSSL version: OpenSSL 1.0.1t 3 May 2016

In this setup, running on CentOS 7.x, am able to push and pull docker images without any issues.

From the UI, while trying to access the images i.e. clicking on the tag assigned to the image, UI display this in red color,

Unknown errors have occurred. Please try again later.

This is the URL being accessed. In fact, I have couple of test images and accessing their tag throws up the above error.
http://private-ip-address/harbor/projects/1/repositories/library%2Falpine/tags/latest

a) Have checked /var/log/harbor/ui.log, could not locate severe errors.

b) FWIW, in the /var/log/harbor/registry.log, there are lot of these error messages. Are they related ?

level=error msg="response completed with error" auth.user.name=admin err.code="blob unknown" err.detail=sha256:705703b2f7e54a835690dacb2cb1f681d03a3b5e15e093aed54cbf7065556cb0 err.message="blob unknown to registry"

[LoLei]

https://github.com/vmware/harbor/issues/5055

Apparently this happens when the tag detail view is accesses without Clair installed. (https://github.com/vmware/harbor/issues/5055#issuecomment-393331527)

[mramanathan]

Did a fresh install of Harbor with Clair and Notary enabled, now the UI errors are not seen.

[reasonerjt]

Let's track it via #5055 closing this one as dup.