Rolling Upgrade Failing

[Paul Russell <pa...@qflow.com>]

I have done several SOLR upgrades without any issues but Im getting the
error below after upgrading the 1st of the 3 nodes in a cluster.

All nodes were running SOLR 6.6.0. I shutdown one of the replica nodes and
did the upgrade to SOLR 7.7.3. The cluster has a SOLR 6 index.. When I
start this node it comes up fine and joins the cluster but the replica on
this node will not come on line. the upgraded node does not report any
errors. The error below comes from the leader. Has anyone seen this before:

2020-12-11 14:31:30.733 WARN  (qtp1800890735-57149) [c:Production s:shard1
r:core_node4 x:Production_shard1_replica4]
o.a.s.u.p.DistributedUpdateProcessor Error sending update to
http://solrnode:8983/solr <http://rdxrddm0040:8983/solr>

org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException: Error
from server at http://solrnode:8983/solr/Production_shard1_replica3
<http://rdxrddm0040:8983/solr/ECFProduction_shard1_replica3>: Expected mime
type application/octet-stream but got application/json. {

  "error":{

    "metadata":[

      "error-class","org.apache.solr.common.SolrException",

      "root-error-class","org.apache.solr.common.SolrException"],

    "msg":"SolrCore is loading",

    "code":503}}



        at
org.apache.solr.client.solrj.impl.HttpSolrClient.executeMethod(HttpSolrClient.java:578)

        at
org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:279)

        at
org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:268)

        at
org.apache.solr.client.solrj.impl.ConcurrentUpdateSolrClient.request(ConcurrentUpdateSolrClient.java:430)

        at
org.apache.solr.client.solrj.SolrClient.request(SolrClient.java:1219)

        at
org.apache.solr.update.SolrCmdDistributor.doRequest(SolrCmdDistributor.java:299)

        at
org.apache.solr.update.SolrCmdDistributor.lambda$submit$0(SolrCmdDistributor.java:288)

        at java.util.concurrent.FutureTask.run(FutureTask.java:266)

        at
java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)

        at java.util.concurrent.FutureTask.run(FutureTask.java:266)

        at
com.codahale.metrics.InstrumentedExecutorService$InstrumentedRunnable.run(InstrumentedExecutorService.java:176)

        at
org.apache.solr.common.util.ExecutorUtil$MDCAwareThreadPoolExecutor.lambda$execute$0(ExecutorUtil.java:229)

        at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

        at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

        at java.lang.Thread.run(Thread.java:748)

-- 
*Paul Russell*
*www.qflow.com <http://www.qflow.com>*