Drop dependency of TiDB for host info
Feature Request
Is your feature request related to a problem? Please describe:
Currently host info send queries to TiDB, which has several disadvantages:
- The instance list may not be identical with the one in "instance" tab
- Doesn't work when there is no TiDB
- More potential bugs: A TiDB bug will break the functionality as well, even if original API works well.
Describe the feature you'd like:
Update the host info module to call debug API of each component directly.
Describe alternatives you've considered:
Teachability, Documentation, Adoption, Migration Strategy:
I didn't find the implemented debug API to get host info in pd/tidb/tikv repos (only found /debug/pprof), so we should implement the API in pd/tidv/tikv first?
The implementation for TiDB and PD is in https://github.com/pingcap/sysutil.
We can start from dropping the dependency of CLUSTER_INFO table first, then CLUSTER_HARDWARE.