[SERVER-34342] FCV is "3.2" for new 3.4 replica set with clusterMode: shardsvr Created: 05/Apr/18 Updated: 27/Oct/23 Resolved: 06/Apr/18 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Sharding, Upgrade/Downgrade |
| Affects Version/s: | 3.4.14 |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Minor - P4 |
| Reporter: | Spencer Brown | Assignee: | Unassigned |
| Resolution: | Works as Designed | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Operating System: | ALL | ||||||||||||||||||
| Steps To Reproduce: |
output is:
Expected output is that the FCV is "3.4" as this is a new replica set. |
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| Participants: | |||||||||||||||||||
| Description |
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Starting a new single member 3.4.14 replica set with no data, and the configuration includes sharding.clusterRole: shardsvr, causes the featureCompatibilityVersion to be reported as "3.2". Removing the sharding.clusterRole: shardsvr option and restarting the mongod does not change the FCV to "3.4". However starting a new single member replica set (no data) without shardsvr works correctly, showing FCV of "3.4", and restarting it with shardsvr also still shows FCV of "3.4". Note that there is no FCV document in admin.system.version during all this. Running setFeatureCompatibilityVersion: "3.4" works to set the FCV to 3.4, so this issue is only about what FCV is assumed when you start a brand new replica set. |
| Comments |
| Comment by Eric Milkie [ 06/Apr/18 ] |
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The behavior as described is expected. |
| Comment by Spencer Brown [ 06/Apr/18 ] |
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Indeed, testing shows that once the new 3.4.14 replica set with sharding.clusterRole: shardsvr is added to the sharded cluster, the FCV becomes "3.4", and a FCV document has been added to admin.system.version. |
| Comment by Andy Schwerin [ 05/Apr/18 ] |
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Nodes started with shardsvr in version N must assume fcv N-1 until they are added to the a cluster, in case that cluster is still at fcv N-1. Adding the shard to an fcv N cluster should cause the shard to upgrade to fcv N as well. |
| Comment by Eric Milkie [ 05/Apr/18 ] |
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I think you have to finish setting up sharding before you start looking at FCV reporting. |