Update the "exclusive" section

eric-hu · web-flow · commit f2651f2da1ab · 2017-09-11T20:23:24.000+07:00
Add suggestions for how users should configure jobs with the `exclusive` option. More context here: https://circleci.slack.com/archives/C0B6W2U0L/p1505132677000540
diff --git a/jekyll/_cci2/docker-layer-caching.md b/jekyll/_cci2/docker-layer-caching.md
@@ -33,4 +33,4 @@ The second option (`exclusive`) indicates whether you want to allow parallel job
 
 If you set `exclusive:` to `false`, the project's parallel jobs will be able to share the same Remote Docker Environment. This method lets you reduce the chances of receiving a Remote Docker Environment without a cache. If you choose this option, ensure that your project can handle concurrent operations in Docker Engine.
 
-For example, if you build images with mutable tags like `latest`, then a shared Docker environment could have undesireable results. When `exclusive:` is set to `false`, CircleCI only allows two parallel jobs to use the same Docker environment.
+For example, if you build images with mutable tags like `latest`, then a shared Docker environment could have undesireable results. When `exclusive:` is set to `false`, CircleCI only allows two parallel jobs to use the same Docker environment.  This can be any 2 jobs running in parallel in the same project.  For example, `build 2` on job 1 and `deploy 1` on job 2 could share the same environment.  As such, you should not assume sequential sharing, where the `build 1` environment is the same one that `test 1` uses in a job.  Instead, each job should be configured to push or pull to a Docker registry as needed.  The Docker environments will eventually stabilize with the images your jobs require after a few job runs.

Original file line number	Diff line number	Diff line change
@@ -33,4 +33,4 @@ The second option (`exclusive`) indicates whether you want to allow parallel job
`33`	`33`
`34`	`34`	If you set `exclusive:` to `false`, the project's parallel jobs will be able to share the same Remote Docker Environment. This method lets you reduce the chances of receiving a Remote Docker Environment without a cache. If you choose this option, ensure that your project can handle concurrent operations in Docker Engine.
`35`	`35`
`36`		-For example, if you build images with mutable tags like `latest`, then a shared Docker environment could have undesireable results. When `exclusive:` is set to `false`, CircleCI only allows two parallel jobs to use the same Docker environment.
	`36`	+For example, if you build images with mutable tags like `latest`, then a shared Docker environment could have undesireable results. When `exclusive:` is set to `false`, CircleCI only allows two parallel jobs to use the same Docker environment. This can be any 2 jobs running in parallel in the same project. For example, `build 2` on job 1 and `deploy 1` on job 2 could share the same environment. As such, you should not assume sequential sharing, where the `build 1` environment is the same one that `test 1` uses in a job. Instead, each job should be configured to push or pull to a Docker registry as needed. The Docker environments will eventually stabilize with the images your jobs require after a few job runs.