Support multi-instance high availability cloudcore for large-scale cluster

[fisherxu]

What would you like to be added/modified:
Support multi-instance high availability cloudcore in cloudside, so we can spport large-scale cluster.

Why is this needed:
Cloudcore is the core component of kubeegde in cloud, which is responsible for sending resources of cloud to the edge. Now the cloudcore is running in leader/follower mode, only one instance can run at the same time. For the more larger scale cluster, we need to support multi-instance high availability for cloudcore.

[akdanwlf]

Hello @fisherxu, I came across this issue listed as an LFX Mentorship Project. I am trying to join the kubeedge Slack channel, but it looks like the invitation present in CONTRIBUTING.md is expired. Can I find the link to join elsewhere?

[fisherxu]

Hello @fisherxu, I came across this issue listed as an LFX Mentorship Project. I am trying to join the kubeedge Slack channel, but it looks like the invitation present in CONTRIBUTING.md is expired. Can I find the link to join elsewhere?

@akdanwlf Please try this one :) https://join.slack.com/t/kubeedge/shared_invite/enQtNjc0MTg2NTg2MTk0LWJmOTBmOGRkZWNhMTVkNGU1ZjkwNDY4MTY4YTAwNDAyMjRkMjdlMjIzYmMxODY1NGZjYzc4MWM5YmIxZjU1ZDI

[kevin-wangzefeng]

Previous disscussion #1444

[stale]

Hello 👋 Looks like there was no activity on this issue for last 90 days.
Do you mind updating us on the status? Is this still reproducible or needed? If yes, just comment on this PR or push a commit. Thanks! 🤗
If there will be no activity for 60 days, this issue will be closed (we can always reopen an issue if we need!).

[stale]

Closing for now as there was no activity for last 60 days after marked as stale, let us know if you need this to be reopened! 🤗