Re: [DISCUSS] Drop Zookeeper 3.4
After FLINK-10052[1], which was merged in 1.14.0, rolling upgrading ZooKeeper will not affect the running Flink application. 1. https://issues.apache.org/jira/browse/FLINK-10052 Best, Yang Chesnay Schepler 于2021年12月7日周二 下午4:37写道: > Since this is only relevant for 1.15, if you intend to migrate to 1.15 > close to the release, then somewhere around February. > > The only resource I could find for migrating Zookeeper is this FAQ: > https://cwiki.apache.org/confluence/display/ZOOKEEPER/Upgrade+FAQ > > On 07/12/2021 04:02, Dongwon Kim wrote: > > When should I prepare for upgrading ZK to 3.5 or newer? > We're operating a Hadoop cluster w/ ZK 3.4.6 for running only Flink jobs. > Just hope that the rolling update is not that painful - any advice on this? > > Best, > > Dongwon > > On Tue, Dec 7, 2021 at 3:22 AM Chesnay Schepler > wrote: > >> Current users of ZK 3.4 and below would need to upgrade their Zookeeper >> installation that is used by Flink to 3.5+. >> >> Whether K8s users are affected depends on whether they use ZK or not. If >> they do, see above, otherwise they are not affected at all. >> >> On 06/12/2021 18:49, Arvid Heise wrote: >> >> Could someone please help me understand the implications of the upgrade? >> >> As far as I understood this upgrade would only affect users that have a >> zookeeper shared across multiple services, some of which require ZK 3.4-? A >> workaround for those users would be to run two ZKs with different versions, >> eventually deprecating old ZK, correct? >> >> If that is the only limitation, I'm +1 for the proposal since ZK 3.4 is >> already EOL. >> >> How are K8s users affected? >> >> Best, >> >> Arvid >> >> On Mon, Dec 6, 2021 at 2:00 PM Chesnay Schepler >> wrote: >> >>> ping @users; any input on how this would affect you is highly >>> appreciated. >>> >>> On 25/11/2021 22:39, Chesnay Schepler wrote: >>> > I included the user ML in the thread. >>> > >>> > @users Are you still using Zookeeper 3.4? If so, were you planning to >>> > upgrade Zookeeper in the near future? >>> > >>> > I'm not sure about ZK compatibility, but we'd also upgrade Curator to >>> > 5.x, which doesn't support ookeeperK 3.4 anymore. >>> > >>> > On 25/11/2021 21:56, Till Rohrmann wrote: >>> >> Should we ask on the user mailing list whether anybody is still using >>> >> ZooKeeper 3.4 and thus needs support for this version or can a >>> ZooKeeper >>> >> 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect that >>> >> not a >>> >> lot of users depend on it but just to make sure that we aren't >>> >> annoying a >>> >> lot of our users with this change. Apart from that +1 for removing it >>> if >>> >> not a lot of user depend on it. >>> >> >>> >> Cheers, >>> >> Till >>> >> >>> >> On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl < >>> matth...@ververica.com> >>> >> wrote: >>> >> >>> >>> Thanks for starting this discussion, Chesnay. +1 from my side. It's >>> >>> time to >>> >>> move forward with the ZK support considering the EOL of 3.4 you >>> already >>> >>> mentioned. The benefits we gain from upgrading Curator to 5.x as a >>> >>> consequence is another plus point. Just for reference on the >>> >>> inconsistent >>> >>> state issue you mentioned: FLINK-24543 [1]. >>> >>> >>> >>> Matthias >>> >>> >>> >>> [1] https://issues.apache.org/jira/browse/FLINK-24543 >>> >>> >>> >>> On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler < >>> ches...@apache.org> >>> >>> wrote: >>> >>> >>> Hello, >>> >>> I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading the >>> default to 3.5 with an opt-in for 3.6. >>> >>> Supporting Zookeeper 3.4 (which is already EOL) prevents us from >>> upgrading Curator to 5.x, which would allow us to properly fix an >>> issue >>> with inconsistent state. It is also required to eventually support >>> ZK >>> >>> 3.6. >>> > >>> > >>> >>> >> >
Re: [DISCUSS] Drop Zookeeper 3.4
Since this is only relevant for 1.15, if you intend to migrate to 1.15 close to the release, then somewhere around February. The only resource I could find for migrating Zookeeper is this FAQ: https://cwiki.apache.org/confluence/display/ZOOKEEPER/Upgrade+FAQ On 07/12/2021 04:02, Dongwon Kim wrote: When should I prepare for upgrading ZK to 3.5 or newer? We're operating a Hadoop cluster w/ ZK 3.4.6 for running only Flink jobs. Just hope that the rolling update is not that painful - any advice on this? Best, Dongwon On Tue, Dec 7, 2021 at 3:22 AM Chesnay Schepler wrote: Current users of ZK 3.4 and below would need to upgrade their Zookeeper installation that is used by Flink to 3.5+. Whether K8s users are affected depends on whether they use ZK or not. If they do, see above, otherwise they are not affected at all. On 06/12/2021 18:49, Arvid Heise wrote: Could someone please help me understand the implications of the upgrade? As far as I understood this upgrade would only affect users that have a zookeeper shared across multiple services, some of which require ZK 3.4-? A workaround for those users would be to run two ZKs with different versions, eventually deprecating old ZK, correct? If that is the only limitation, I'm +1 for the proposal since ZK 3.4 is already EOL. How are K8s users affected? Best, Arvid On Mon, Dec 6, 2021 at 2:00 PM Chesnay Schepler wrote: ping @users; any input on how this would affect you is highly appreciated. On 25/11/2021 22:39, Chesnay Schepler wrote: > I included the user ML in the thread. > > @users Are you still using Zookeeper 3.4? If so, were you planning to > upgrade Zookeeper in the near future? > > I'm not sure about ZK compatibility, but we'd also upgrade Curator to > 5.x, which doesn't support ookeeperK 3.4 anymore. > > On 25/11/2021 21:56, Till Rohrmann wrote: >> Should we ask on the user mailing list whether anybody is still using >> ZooKeeper 3.4 and thus needs support for this version or can a ZooKeeper >> 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect that >> not a >> lot of users depend on it but just to make sure that we aren't >> annoying a >> lot of our users with this change. Apart from that +1 for removing it if >> not a lot of user depend on it. >> >> Cheers, >> Till >> >> On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl >> wrote: >> >>> Thanks for starting this discussion, Chesnay. +1 from my side. It's >>> time to >>> move forward with the ZK support considering the EOL of 3.4 you already >>> mentioned. The benefits we gain from upgrading Curator to 5.x as a >>> consequence is another plus point. Just for reference on the >>> inconsistent >>> state issue you mentioned: FLINK-24543 [1]. >>> >>> Matthias >>> >>> [1] https://issues.apache.org/jira/browse/FLINK-24543 >>> >>> On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler >>> wrote: >>> Hello, I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading the default to 3.5 with an opt-in for 3.6. Supporting Zookeeper 3.4 (which is already EOL) prevents us from upgrading Curator to 5.x, which would allow us to properly fix an issue with inconsistent state. It is also required to eventually support ZK >>> 3.6. > >
Re: [DISCUSS] Drop Zookeeper 3.4
When should I prepare for upgrading ZK to 3.5 or newer? We're operating a Hadoop cluster w/ ZK 3.4.6 for running only Flink jobs. Just hope that the rolling update is not that painful - any advice on this? Best, Dongwon On Tue, Dec 7, 2021 at 3:22 AM Chesnay Schepler wrote: > Current users of ZK 3.4 and below would need to upgrade their Zookeeper > installation that is used by Flink to 3.5+. > > Whether K8s users are affected depends on whether they use ZK or not. If > they do, see above, otherwise they are not affected at all. > > On 06/12/2021 18:49, Arvid Heise wrote: > > Could someone please help me understand the implications of the upgrade? > > As far as I understood this upgrade would only affect users that have a > zookeeper shared across multiple services, some of which require ZK 3.4-? A > workaround for those users would be to run two ZKs with different versions, > eventually deprecating old ZK, correct? > > If that is the only limitation, I'm +1 for the proposal since ZK 3.4 is > already EOL. > > How are K8s users affected? > > Best, > > Arvid > > On Mon, Dec 6, 2021 at 2:00 PM Chesnay Schepler > wrote: > >> ping @users; any input on how this would affect you is highly appreciated. >> >> On 25/11/2021 22:39, Chesnay Schepler wrote: >> > I included the user ML in the thread. >> > >> > @users Are you still using Zookeeper 3.4? If so, were you planning to >> > upgrade Zookeeper in the near future? >> > >> > I'm not sure about ZK compatibility, but we'd also upgrade Curator to >> > 5.x, which doesn't support ookeeperK 3.4 anymore. >> > >> > On 25/11/2021 21:56, Till Rohrmann wrote: >> >> Should we ask on the user mailing list whether anybody is still using >> >> ZooKeeper 3.4 and thus needs support for this version or can a >> ZooKeeper >> >> 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect that >> >> not a >> >> lot of users depend on it but just to make sure that we aren't >> >> annoying a >> >> lot of our users with this change. Apart from that +1 for removing it >> if >> >> not a lot of user depend on it. >> >> >> >> Cheers, >> >> Till >> >> >> >> On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl > > >> >> wrote: >> >> >> >>> Thanks for starting this discussion, Chesnay. +1 from my side. It's >> >>> time to >> >>> move forward with the ZK support considering the EOL of 3.4 you >> already >> >>> mentioned. The benefits we gain from upgrading Curator to 5.x as a >> >>> consequence is another plus point. Just for reference on the >> >>> inconsistent >> >>> state issue you mentioned: FLINK-24543 [1]. >> >>> >> >>> Matthias >> >>> >> >>> [1] https://issues.apache.org/jira/browse/FLINK-24543 >> >>> >> >>> On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler > > >> >>> wrote: >> >>> >> Hello, >> >> I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading the >> default to 3.5 with an opt-in for 3.6. >> >> Supporting Zookeeper 3.4 (which is already EOL) prevents us from >> upgrading Curator to 5.x, which would allow us to properly fix an >> issue >> with inconsistent state. It is also required to eventually support ZK >> >>> 3.6. >> > >> > >> >> >
Re: [DISCUSS] Drop Zookeeper 3.4
FYI: We(Alibaba) are widely using ZooKeeper 3.5.5 for all the YARN and some K8s Flink high-available applications. Best, Yang Chesnay Schepler 于2021年12月7日周二 上午2:22写道: > Current users of ZK 3.4 and below would need to upgrade their Zookeeper > installation that is used by Flink to 3.5+. > > Whether K8s users are affected depends on whether they use ZK or not. If > they do, see above, otherwise they are not affected at all. > > On 06/12/2021 18:49, Arvid Heise wrote: > > Could someone please help me understand the implications of the upgrade? > > > > As far as I understood this upgrade would only affect users that have > > a zookeeper shared across multiple services, some of which require ZK > > 3.4-? A workaround for those users would be to run two ZKs with > > different versions, eventually deprecating old ZK, correct? > > > > If that is the only limitation, I'm +1 for the proposal since ZK 3.4 > > is already EOL. > > > > How are K8s users affected? > > > > Best, > > > > Arvid > > > > On Mon, Dec 6, 2021 at 2:00 PM Chesnay Schepler > > wrote: > > > > ping @users; any input on how this would affect you is highly > > appreciated. > > > > On 25/11/2021 22:39, Chesnay Schepler wrote: > > > I included the user ML in the thread. > > > > > > @users Are you still using Zookeeper 3.4? If so, were you > > planning to > > > upgrade Zookeeper in the near future? > > > > > > I'm not sure about ZK compatibility, but we'd also upgrade > > Curator to > > > 5.x, which doesn't support ookeeperK 3.4 anymore. > > > > > > On 25/11/2021 21:56, Till Rohrmann wrote: > > >> Should we ask on the user mailing list whether anybody is still > > using > > >> ZooKeeper 3.4 and thus needs support for this version or can a > > ZooKeeper > > >> 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect > > that > > >> not a > > >> lot of users depend on it but just to make sure that we aren't > > >> annoying a > > >> lot of our users with this change. Apart from that +1 for > > removing it if > > >> not a lot of user depend on it. > > >> > > >> Cheers, > > >> Till > > >> > > >> On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl > > > > >> wrote: > > >> > > >>> Thanks for starting this discussion, Chesnay. +1 from my side. > > It's > > >>> time to > > >>> move forward with the ZK support considering the EOL of 3.4 > > you already > > >>> mentioned. The benefits we gain from upgrading Curator to 5.x as > a > > >>> consequence is another plus point. Just for reference on the > > >>> inconsistent > > >>> state issue you mentioned: FLINK-24543 [1]. > > >>> > > >>> Matthias > > >>> > > >>> [1] https://issues.apache.org/jira/browse/FLINK-24543 > > >>> > > >>> On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler > > > > >>> wrote: > > >>> > > Hello, > > > > I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading > the > > default to 3.5 with an opt-in for 3.6. > > > > Supporting Zookeeper 3.4 (which is already EOL) prevents us from > > upgrading Curator to 5.x, which would allow us to properly > > fix an > > issue > > with inconsistent state. It is also required to eventually > > support ZK > > >>> 3.6. > > > > > > > > >
Re: [DISCUSS] Drop Zookeeper 3.4
Current users of ZK 3.4 and below would need to upgrade their Zookeeper installation that is used by Flink to 3.5+. Whether K8s users are affected depends on whether they use ZK or not. If they do, see above, otherwise they are not affected at all. On 06/12/2021 18:49, Arvid Heise wrote: Could someone please help me understand the implications of the upgrade? As far as I understood this upgrade would only affect users that have a zookeeper shared across multiple services, some of which require ZK 3.4-? A workaround for those users would be to run two ZKs with different versions, eventually deprecating old ZK, correct? If that is the only limitation, I'm +1 for the proposal since ZK 3.4 is already EOL. How are K8s users affected? Best, Arvid On Mon, Dec 6, 2021 at 2:00 PM Chesnay Schepler wrote: ping @users; any input on how this would affect you is highly appreciated. On 25/11/2021 22:39, Chesnay Schepler wrote: > I included the user ML in the thread. > > @users Are you still using Zookeeper 3.4? If so, were you planning to > upgrade Zookeeper in the near future? > > I'm not sure about ZK compatibility, but we'd also upgrade Curator to > 5.x, which doesn't support ookeeperK 3.4 anymore. > > On 25/11/2021 21:56, Till Rohrmann wrote: >> Should we ask on the user mailing list whether anybody is still using >> ZooKeeper 3.4 and thus needs support for this version or can a ZooKeeper >> 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect that >> not a >> lot of users depend on it but just to make sure that we aren't >> annoying a >> lot of our users with this change. Apart from that +1 for removing it if >> not a lot of user depend on it. >> >> Cheers, >> Till >> >> On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl >> wrote: >> >>> Thanks for starting this discussion, Chesnay. +1 from my side. It's >>> time to >>> move forward with the ZK support considering the EOL of 3.4 you already >>> mentioned. The benefits we gain from upgrading Curator to 5.x as a >>> consequence is another plus point. Just for reference on the >>> inconsistent >>> state issue you mentioned: FLINK-24543 [1]. >>> >>> Matthias >>> >>> [1] https://issues.apache.org/jira/browse/FLINK-24543 >>> >>> On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler >>> wrote: >>> Hello, I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading the default to 3.5 with an opt-in for 3.6. Supporting Zookeeper 3.4 (which is already EOL) prevents us from upgrading Curator to 5.x, which would allow us to properly fix an issue with inconsistent state. It is also required to eventually support ZK >>> 3.6. > >
Re: [DISCUSS] Drop Zookeeper 3.4
Could someone please help me understand the implications of the upgrade? As far as I understood this upgrade would only affect users that have a zookeeper shared across multiple services, some of which require ZK 3.4-? A workaround for those users would be to run two ZKs with different versions, eventually deprecating old ZK, correct? If that is the only limitation, I'm +1 for the proposal since ZK 3.4 is already EOL. How are K8s users affected? Best, Arvid On Mon, Dec 6, 2021 at 2:00 PM Chesnay Schepler wrote: > ping @users; any input on how this would affect you is highly appreciated. > > On 25/11/2021 22:39, Chesnay Schepler wrote: > > I included the user ML in the thread. > > > > @users Are you still using Zookeeper 3.4? If so, were you planning to > > upgrade Zookeeper in the near future? > > > > I'm not sure about ZK compatibility, but we'd also upgrade Curator to > > 5.x, which doesn't support ookeeperK 3.4 anymore. > > > > On 25/11/2021 21:56, Till Rohrmann wrote: > >> Should we ask on the user mailing list whether anybody is still using > >> ZooKeeper 3.4 and thus needs support for this version or can a ZooKeeper > >> 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect that > >> not a > >> lot of users depend on it but just to make sure that we aren't > >> annoying a > >> lot of our users with this change. Apart from that +1 for removing it if > >> not a lot of user depend on it. > >> > >> Cheers, > >> Till > >> > >> On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl > >> wrote: > >> > >>> Thanks for starting this discussion, Chesnay. +1 from my side. It's > >>> time to > >>> move forward with the ZK support considering the EOL of 3.4 you already > >>> mentioned. The benefits we gain from upgrading Curator to 5.x as a > >>> consequence is another plus point. Just for reference on the > >>> inconsistent > >>> state issue you mentioned: FLINK-24543 [1]. > >>> > >>> Matthias > >>> > >>> [1] https://issues.apache.org/jira/browse/FLINK-24543 > >>> > >>> On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler > >>> wrote: > >>> > Hello, > > I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading the > default to 3.5 with an opt-in for 3.6. > > Supporting Zookeeper 3.4 (which is already EOL) prevents us from > upgrading Curator to 5.x, which would allow us to properly fix an > issue > with inconsistent state. It is also required to eventually support ZK > >>> 3.6. > > > > > >
Re: [DISCUSS] Drop Zookeeper 3.4
ping @users; any input on how this would affect you is highly appreciated. On 25/11/2021 22:39, Chesnay Schepler wrote: I included the user ML in the thread. @users Are you still using Zookeeper 3.4? If so, were you planning to upgrade Zookeeper in the near future? I'm not sure about ZK compatibility, but we'd also upgrade Curator to 5.x, which doesn't support ookeeperK 3.4 anymore. On 25/11/2021 21:56, Till Rohrmann wrote: Should we ask on the user mailing list whether anybody is still using ZooKeeper 3.4 and thus needs support for this version or can a ZooKeeper 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect that not a lot of users depend on it but just to make sure that we aren't annoying a lot of our users with this change. Apart from that +1 for removing it if not a lot of user depend on it. Cheers, Till On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl wrote: Thanks for starting this discussion, Chesnay. +1 from my side. It's time to move forward with the ZK support considering the EOL of 3.4 you already mentioned. The benefits we gain from upgrading Curator to 5.x as a consequence is another plus point. Just for reference on the inconsistent state issue you mentioned: FLINK-24543 [1]. Matthias [1] https://issues.apache.org/jira/browse/FLINK-24543 On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler wrote: Hello, I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading the default to 3.5 with an opt-in for 3.6. Supporting Zookeeper 3.4 (which is already EOL) prevents us from upgrading Curator to 5.x, which would allow us to properly fix an issue with inconsistent state. It is also required to eventually support ZK 3.6.
Re: [DISCUSS] Drop Zookeeper 3.4
According to this SO question [1], it seems that Zk 3.5 clients cannot talk to 3.4 servers. I also tried it out with a local deployment and Flink was not able to start. Newer Zk versions can talk to older Zk servers if no new APIs are used [2]. [1] https://stackoverflow.com/a/61630617/4815083 [2] https://zookeeper.apache.org/releases.html Cheers, Till On Thu, Nov 25, 2021 at 10:39 PM Chesnay Schepler wrote: > I included the user ML in the thread. > > @users Are you still using Zookeeper 3.4? If so, were you planning to > upgrade Zookeeper in the near future? > > I'm not sure about ZK compatibility, but we'd also upgrade Curator to > 5.x, which doesn't support ookeeperK 3.4 anymore. > > On 25/11/2021 21:56, Till Rohrmann wrote: > > Should we ask on the user mailing list whether anybody is still using > > ZooKeeper 3.4 and thus needs support for this version or can a ZooKeeper > > 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect that not a > > lot of users depend on it but just to make sure that we aren't annoying a > > lot of our users with this change. Apart from that +1 for removing it if > > not a lot of user depend on it. > > > > Cheers, > > Till > > > > On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl > > wrote: > > > >> Thanks for starting this discussion, Chesnay. +1 from my side. It's > time to > >> move forward with the ZK support considering the EOL of 3.4 you already > >> mentioned. The benefits we gain from upgrading Curator to 5.x as a > >> consequence is another plus point. Just for reference on the > inconsistent > >> state issue you mentioned: FLINK-24543 [1]. > >> > >> Matthias > >> > >> [1] https://issues.apache.org/jira/browse/FLINK-24543 > >> > >> On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler > >> wrote: > >> > >>> Hello, > >>> > >>> I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading the > >>> default to 3.5 with an opt-in for 3.6. > >>> > >>> Supporting Zookeeper 3.4 (which is already EOL) prevents us from > >>> upgrading Curator to 5.x, which would allow us to properly fix an issue > >>> with inconsistent state. It is also required to eventually support ZK > >> 3.6. > > >
Re: [DISCUSS] Drop Zookeeper 3.4
I included the user ML in the thread. @users Are you still using Zookeeper 3.4? If so, were you planning to upgrade Zookeeper in the near future? I'm not sure about ZK compatibility, but we'd also upgrade Curator to 5.x, which doesn't support ookeeperK 3.4 anymore. On 25/11/2021 21:56, Till Rohrmann wrote: Should we ask on the user mailing list whether anybody is still using ZooKeeper 3.4 and thus needs support for this version or can a ZooKeeper 3.5/3.6 client talk to a ZooKeeper 3.4 cluster? I would expect that not a lot of users depend on it but just to make sure that we aren't annoying a lot of our users with this change. Apart from that +1 for removing it if not a lot of user depend on it. Cheers, Till On Wed, Nov 24, 2021 at 11:03 AM Matthias Pohl wrote: Thanks for starting this discussion, Chesnay. +1 from my side. It's time to move forward with the ZK support considering the EOL of 3.4 you already mentioned. The benefits we gain from upgrading Curator to 5.x as a consequence is another plus point. Just for reference on the inconsistent state issue you mentioned: FLINK-24543 [1]. Matthias [1] https://issues.apache.org/jira/browse/FLINK-24543 On Wed, Nov 24, 2021 at 10:19 AM Chesnay Schepler wrote: Hello, I'd like to drop support for Zookeeper 3.4 in 1.15, upgrading the default to 3.5 with an opt-in for 3.6. Supporting Zookeeper 3.4 (which is already EOL) prevents us from upgrading Curator to 5.x, which would allow us to properly fix an issue with inconsistent state. It is also required to eventually support ZK 3.6.