Reduct jitter feature

[King-Dylan]

Feature Request

Reduct jitter feature
Is your feature request related to a problem? Please describe:

• before upgrade check pd miss-peer pending-peer and give a suggestion :solve miss-peer or ignore . Check the status of the region before the upgrade to reduce upgrade jitter or failure caused by the abnormal region before the upgrade.
• before eviting tikv leader configure leader-scheduler-limit store-limit region-scheduler-limit.speed up leader transfer, after upgrade change to default value。can take the original value and add a number, and make a judgment of not greater than leader-scheduler-limit(64) store-limit(1024) region-scheduler-limit(1024) example:
  1.tiup cluster upgrade xxxx
  2.background(get default value)
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 config show |grep leader-schedule-limit
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 config show |grep region-schedule-limit
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 store limit
  3.background
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 config set leader-schedule-limit {default value}+32
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 config set region-schedule-limit {default value}+512
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 store limit all {default value}+512
  4.tikv rolling upgrade end
  5.background(get value and check default >=0)
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 config show |grep leader-schedule-limit
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 config show |grep region-schedule-limit
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 store limit
  6.background (setback default value)
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 config set leader-schedule-limit {value}-32
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 config set region-schedule-limit {value}-512
  tiup ctl pd -u xxx.xxx.xxx.xxx:2379 store limit all {value}-512

Describe the feature you'd like:

Describe alternatives you've considered:

Teachability, Documentation, Adoption, Migration Strategy:

[King-Dylan]

pd reduce jitter:
when rolling restart PD, confirm that each peers can server : #1032
Upgrade pd that is not leader first then upgrade pd leader in tiup upgrade: #664

[AstroProfundis]

I'm closing this as both linked issues are closed, please reopen if there's anything more need to be done.