# Elasticsearch 6.8.x and two versions of OpenJDK **URL:** \ **Category:** Elasticsearch\ **Created:** [May 30, 2020, 11:51pm UTC](https://discuss.elastic.co/t/elasticsearch-6-8-x-and-two-versions-of-openjdk/235039 "2020-05-30T23:51:37Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![lazyusername](https://avatars.discourse-cdn.com/v4/letter/l/278dde/32.png) [@lazyusername](https://discuss.elastic.co/u/lazyusername)\ **Post date:** [May 30, 2020, 11:51pm UTC](https://discuss.elastic.co/t/elasticsearch-6-8-x-and-two-versions-of-openjdk/235039/1 "2020-05-30T23:51:37Z")
Hello, we have some mid sized cluster around ~70 nodes running on Debian Stretch (9.x) with OpenJDK-8. We will need to add some extra nodes with Debian Buster, where is present OpenJDK-11. Both versions of OpenJDK is ok with Elasticsearch 6.8.6 according to compatibiltiy matrix. But is it possible to run cluster with some nodes with OpenJDK-8 and some nodes with OpenJDK-11? Thx for answer guys! ---
**Author:** ![lazyusername](https://avatars.discourse-cdn.com/v4/letter/l/278dde/32.png) [@lazyusername](https://discuss.elastic.co/u/lazyusername)\ **Post date:** [May 31, 2020, 4:22pm UTC](https://discuss.elastic.co/t/elasticsearch-6-8-x-and-two-versions-of-openjdk/235039/2 "2020-05-31T16:22:41Z")
I surely could try to use backported OpenJDK-11 on Debian Stretch nodes as prerequisite. But still, I will enter the situation while I will have two parts of cluster: 1. with OpenJDK-8, 2. with OpenJDK-11. I found a lot of info about compatibiltiy client a and server parts to use the same Java. But I am having really hard time to find any info about the various supported java versions on the nodes in the same cluster. Do you have any experience with that guys? ---
**Author:** ![DavidTurner](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/davidturner/32/22453_2.png) [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)\ **Post date:** [May 31, 2020, 5:30pm UTC](https://discuss.elastic.co/t/elasticsearch-6-8-x-and-two-versions-of-openjdk/235039/3 "2020-05-31T17:30:40Z")
Running with mixed JVM versions isn't something we test as far as I can see, and [the manual specifically says not to do this](https://www.elastic.co/guide/en/elasticsearch/reference/6.8/setup.html#jvm-version): > The same JVM version should be used on all Elasticsearch nodes and clients. That's not to say that I know of any specific problems with running with mixed JDK versions. Ultimately it's your data and your call to make. Newer versions (≥7.x) include the recommended JDK in the installation for this very reason. ---
**Author:** ![lazyusername](https://avatars.discourse-cdn.com/v4/letter/l/278dde/32.png) [@lazyusername](https://discuss.elastic.co/u/lazyusername)\ **Post date:** [May 31, 2020, 6:39pm UTC](https://discuss.elastic.co/t/elasticsearch-6-8-x-and-two-versions-of-openjdk/235039/4 "2020-05-31T18:39:52Z")
Thx for reply and info, @DavidTurner! I am aware about the bundled JDK in ES 7.x and that's pretty cool. But sadly we are not at the point of upgrade anytime soon ☹ > The same JVM version should be used on all Elasticsearch nodes and clients. I noticed that, but somehow I read it as the main message is about conjunction of version on nodes _AND_ clients especially. My bad. OK, we will consider to do the upgrade old nodes to backported OpenJDK-11 before adding the new nodes. I was not even sure about the compatibility so we would be able to do the rolling restart at this point. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [June 28, 2020, 6:39pm UTC](https://discuss.elastic.co/t/elasticsearch-6-8-x-and-two-versions-of-openjdk/235039/5 "2020-06-28T18:39:53Z")
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