Run release benchmarks with the bundled JDK (elastic#242)

With this commit we update the release benchmark instructions to run
with the bundled JDK. We also add a clarifying note to the release
legend on the benchmark page.

.github/ISSUE_TEMPLATE/release-benchmarks.md

@@ -13,8 +13,8 @@ For every task below, after scheduling the job, remember to cancel nightly jobs
 If your released job seems to be still running, cancel them (use the x button after logging in on Jenkins) and reschedule using the correct effective start date.
 More details in [night-rally docs](https://github.com/elastic/night-rally/blob/master/42.md#what-time-do-the-nightly-benchmarks-start-what-elasticsearch-commit-do-they-choose).
 
-- [ ] mode: `release`, release_license: `oss` - triggered by `your user handle here`  as `link to all triggered builds here`
-- [ ] mode: `release`, release_license: `basic` - triggered by `your user handle here`  as `link to all triggered builds here`
-- [ ] mode: `release`, RELEASE_LICENSE: `trial` + RELEASE_X_PACK_COMPONENTS: `security` - triggered by `your user handle here`  as `link to all triggered builds here`
+- [ ] mode: `release`, runtime_jdk: `bundled`, release_license: `oss` - triggered by `your user handle here`  as `link to all triggered builds here`
+- [ ] mode: `release`, runtime_jdk: `bundled`, release_license: `basic` - triggered by `your user handle here`  as `link to all triggered builds here`
+- [ ] mode: `release`, runtime_jdk: `bundled`, RELEASE_LICENSE: `trial` + RELEASE_X_PACK_COMPONENTS: `security` - triggered by `your user handle here`  as `link to all triggered builds here`
 - [ ] mode: `release:docker` (everything else default i.e. `oss`) - triggered by `your user handle here`  as `link to all triggered builds here`
-- [ ] mode: `release:encryption-at-rest` (everything else default i.e. `oss`) - triggered by `your user handle here`  as `link to all triggered builds here`
+- [ ] mode: `release:encryption-at-rest`, runtime_jdk: `bundled` (everything else default i.e. `oss`) - triggered by `your user handle here`  as `link to all triggered builds here`

external/pages/index.html

@@ -283,6 +283,7 @@ <h4>Legend</h4>
               <li><code>basic</code>: Elasticsearch with <a href="https://www.elastic.co/subscriptions">commercial Elastic license</a>; see <a href="https://www.elastic.co/products/x-pack/open">x-pack/open</a>.</li>
               <li><code>trial-security</code>: Elasticsearch with <a href="https://www.elastic.co/products/x-pack/security">X-Pack Security and TLS</a> enabled.</li>
           </ul>
+          <p>Starting with Elasticsearch 7.7.0, benchmarks are run with the <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/setup.html#jvm-version">JDK that is bundled with Elasticsearch</a>.</p>
       </div>
     </div>
   </div>