Akka.Cluster.Sharding documentation - need to explain how to shut down entities when remember-entities=on

[Aaronontheweb]

Version: 1.3.16

When running an Akka.Cluster.Sharding setup with storage-mode = persistence and remember-entities = on, it turns out that it is impossible to permanently kill any entity actors even if this is the desired outcome.

I can send along a small reproduction example in short order, but the quick version: entity actors that terminate themselves via Context.Stop are always restarted by Akka.Cluster.Sharding within a few seconds and these actors are also automatically created when an Akka.Cluster.Sharding node recreates following a process restart of a singleton cluster.

[hwanders]

According to the comment on RestartEntity (When an remembering entries and the entity stops without issuing a <see cref="Passivate"/>, we restart it after a back off using this message.) this might be the desired behaviour.

Perhaps calling Context.Stop alone does not convey the desired intent of terminating the entity.
Adding a specific message (Terminate or something similar) would make the API clearer (it might cause the same behaviour as the Passivate message but perhaps there are other cleanup tasks involved). A little paragraph about terminating entities would be a nice addition to the docs.
For persisistent actors there are special steps involved anyway (I guess, manually deleting snapshots and the journal is required).

[ismaelhamed]

@hwanders is right. To permanently stop entities when remember-entities is enabled, use Passivate. Otherwise they will be recreated after a rebalance or restart.

[Aaronontheweb]

In that case, this is a really documentation issue.

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Sent from my iPhone

On Dec 15, 2019, at 12:43 PM, Ismael Hamed ***@***.***> wrote:  @hwanders is right. To permanently stop entities when remember-entities is enabled, use Passivate. Otherwise they will be recreated after a rebalance or restart. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[ismaelhamed]

To further clarify: this behavior should be the same whether the user chooses persistence or ddata as the storage-mode. Except that, according to this #3199 (comment), the current Distributed Data implementation in Akka.NET doesn't support durable storage.

[Aaronontheweb]

I think the issue with DData has to do with its wire format, but @Horusiath would know for certain

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Sent from my iPhone

On Dec 15, 2019, at 1:48 PM, Ismael Hamed ***@***.***> wrote:  To further clarify: this behavior should be the same whether the user chooses persistence or ddata as the storage-mode. Except that, according to this #3199 (comment), the current Distributed Data implementation in Akka.NET doesn't support durable storage. It's worth checking whether this limitation still exists. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or unsubscribe.