tiup needs to access Internet for normal operations

[BusyJay]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

tiup cluster destroy test-cluster

2. What did you expect to see?
   It return success.

3. What did you see instead?

> tiup cluster destroy test-cluster
Failed to start component `cluster`
Error: fetch /3.root.json from mirror(https://tiup-mirrors.pingcap.com) failed: download from https://tiup-mirrors.pingcap.com/3.root.json failed: Get https://tiup-mirrors.pingcap.com/3.root.json: dial tcp: lookup tiup-mirrors.pingcap.com on ip:53: server misbehaving

4. What version of TiUP are you using (tiup --version)?

> tiup --version
v1.3.7 tiup
Go Version: go1.13
Git Branch: release-1.3
GitHash: 37c95bb

[lucklove]

https://github.com/pingcap/tiup/blob/master/doc/design/manifest.md

It's a security mechanism

[lucklove]

TiUP can't decide when to run itself, so the only opportunity to update the root certificate is every time it was called to make sure it's safe.

[BusyJay]

It's a security mechanism

It's too long for me to finish finding useful information for this specific case.

the only opportunity to update the root certificate is every time it was called to make sure it's safe

Why it needs to update root certificate? Why can't it wait till running tiup update? Given that tiup is usually run inside internal network, is it really necessary to check root certificate for potential attacks? If someone gets access to the machine where tiup runs on, it can do more harm than corrupting tiup as they has fully access to ssh keys, cluster lists, etc.

To me, accessing Internet without notice and fail all remaining operations are over-design and not reasonable in all sense.

[kolbe]

tiup should only fetch this information from the internet every 24h (just write a UTC epoch timestamp to ~/.tiup/last_check or something) and failure to fetch the manifests should not be fatal.

Local operations that have to wait every time for costly internet fetches give a very bad user experience, even when they succeed.