add inactive member mamage rule

community-membership.md

@@ -133,8 +133,27 @@ Has deep understanding of Volcano and related domain and facilitates major agree
 - May get admin access to relevant repository based on requirement
 - Participate & Drive design/development of multiple features
 
+## Inactive members
+
+_Members are continuously active contributors in the community._
+
+A core principle in maintaining a healthy community is encouraging active participation. It is inevitable that people's focuses will change over time and they are not expected to be actively contributing forever.
+
+However, serving as a maintainer or approver for one of the Volcano GitHub organizations comes with an elevated set of permissions. These capabilities should not be used by those that are not familiar with the current state of the Volcano project.
+
+Therefore Maintainers or Approver who is extended period away from the project with no activity will be removed from the Volcano Github Organizations and will be required to go through the org membership process again after re-familiarizing themselves with the current state.
+
+### How inactivity is measured
+
+Inactive members are defined as members of one of the Volcano Organizations with **no** contributions across any organization within 18 months. This is measured by the CNCF [DevStats project].
+
+**Note:** Devstats does not take into account non-code contributions. If a non-code contributing member is accidentally removed this way, they may open an issue to quickly be re-instated.
+
+After an extended period away from the project with no activity those members would need to re-familiarize themselves with the current state before being able to contribute effectively.
+
 
 **Note :** These roles are applicable only for Volcano github organization and repositories. Currently Volcano doesn't have a formal process for review and acceptance into these roles. We will come-up with a process soon.
 
 
 [two-factor authentication]: https://help.github.com/articles/about-two-factor-authentication
+[Devstats project]: https://volcano.devstats.cncf.io/