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Posted to users@pulsar.apache.org by Apache Pulsar Slack <ap...@gmail.com> on 2019/04/25 09:11:02 UTC

Slack digest for #general - 2019-04-25

2019-04-24 11:25:02 UTC - Ruud Kamphuis: I made a mistake when I ran `initialize-cluster-metadata`. Is there a way to overwrite this? Or is there a way to remove the entries from ZK and re-apply it?
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2019-04-24 11:26:55 UTC - Sijie Guo: what was the mistake?
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2019-04-24 11:28:36 UTC - Ruud Kamphuis: I set
```
--zookeeper zk-0.zk-hs.pulsar-experiment.svc.cluster.local,zk-1.zk-hs.pulsar-experiment.svc.cluster.local,zk-2.zk-hs.pulsar-experiment.svc.cluster.local \
                --configuration-store zk-0.zk-hs.pulsar-experiment.svc.cluster.local,zk-1.zk-hs.pulsar-experiment.svc.cluster.local,zk-2.zk-hs.pulsar-experiment.svc.cluster.local \
```

instead of

```
--zookeeper zk-cs \
                --configuration-store zk-cs \
```
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2019-04-24 11:51:35 UTC - Sijie Guo: @Ruud Kamphuis I don’t think these settings are stored. so you should be fine.
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2019-04-24 12:05:47 UTC - Ruud Kamphuis: Does somebody have a good example of what values I could enter as tenant? Most of the tutorials use `ten` and `ns` as namespace. But to me, that's the worst example possible. It makes it hard for me to fully understand the concept.

Wouldn't it make sense to always use something recognisable. For example, a tenant can be a team or department inside a company? Correct? For example `data-science`. And then namespace could be something as `etl`, and a topic could be something as `orders` ?

So `data-science/etl/orders` ?
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2019-04-24 12:12:41 UTC - Karthik Ramasamy: @Ruud Kamphuis  - sure
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2019-04-24 12:16:13 UTC - Ezequiel Lovelle: @Ruud Kamphuis yes, I use tenant as a more global entity and namespace as a business unit space
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2019-04-24 12:19:23 UTC - Ruud Kamphuis: And can namespace be something as `etl/path1/path2/path3/path4` and topic `orders` ?  So `data-science/etl/path1/path2/path3/path4/orders`
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2019-04-24 12:24:08 UTC - Ezequiel Lovelle: idk if `/` is a valid char on namespace string, but I don't like that because is counterintuitive with the naming convention of `<persistent://tenant/namespace/topic>`
+1 : Ruud Kamphuis
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2019-04-24 14:55:51 UTC - Grant Wu: I don’t think they use anything more specific than `ten` and `ns` because doing so would imply some sort of opinion on how they’re supposed to be used
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2019-04-24 15:09:37 UTC - Matteo Merli: Tenants and namespaces can only contain alphanum sequences (with-
 `-` and `_`). Topic name is less restrictive and will take all characters, except `/`
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2019-04-24 15:12:18 UTC - Guy Feldman: I use `/` in topic names. does that make it a separate namespace?
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2019-04-24 15:14:50 UTC - Matteo Merli: Problem was maintaining compatibility between pulsar 1.x naming and 2.x. Before it was tenant/cluster/namespace/topic and in 2.0 it got simplified into tenant/namespace/topic. A topic with more slashes would get assumed to be on a 1.x namespace 
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2019-04-24 15:15:41 UTC - Guy Feldman: that explains why it shows up the way it does in topics list
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2019-04-24 15:18:15 UTC - Guy Feldman: it seems to be working though. are there downsides to the assumption of a 1.x namespace?
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2019-04-24 15:18:27 UTC - Guy Feldman: or it will be deprecated
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2019-04-24 15:39:14 UTC - Ruud Kamphuis: I hope it will be deprecated as it's confusing for newcomers. I tried a longer namespace and it worked. But showed up weird in lists.
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2019-04-24 15:40:19 UTC - Ruud Kamphuis: I think it helps newcomers. To me, this feels a bit like `foo` and `bar` examples. Terrible.
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2019-04-24 15:40:52 UTC - Ruud Kamphuis: Docs should explain best practices and not learn people to use `ns` as namespace.
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2019-04-24 16:24:41 UTC - Joe Francis: No deprecations please.
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2019-04-24 16:25:35 UTC - Matteo Merli: The v1 is already “deprecated”, but it would be very hard to drop support, since people have prod deployments with those topic names
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2019-04-24 16:26:34 UTC - Matteo Merli: and a topic name identifies a “resource”. That would make a live migration a very complex task
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2019-04-24 16:26:44 UTC - Joe Francis: One of the aims of Pulsar should be not to make users go through pain to do version upgrades . I know of a very big installation of one another pub-sub system, which is still stuck at a very old versions, because of the cost of upgrades
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2019-04-24 16:30:20 UTC - Ezequiel Lovelle: I don't see v1 as a limiting factor in order to update pulsar, we have around ~5k topics working great with updates so far.
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2019-04-24 16:31:16 UTC - Matteo Merli: The question is that if you drop support for certain features or force migration, that the update will become more painful
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2019-04-24 16:31:47 UTC - Matteo Merli: (even if it’s announced with enough time)
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2019-04-24 16:32:51 UTC - Matteo Merli: that’s why we make sure older clients can talk to newer brokers and so on.
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2019-04-24 16:33:12 UTC - Ezequiel Lovelle: what are the cons of maintaining v1? code maintenance or maybe some future feature blocking?
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2019-04-24 16:33:38 UTC - Matteo Merli: duplication of REST API (mostly in code, documentation is around V2 only)
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2019-04-24 16:33:40 UTC - Joe Francis: It means $$$ to users - apps need to be reworked, tested and redeployed.
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2019-04-24 16:33:57 UTC - Matteo Merli: there are no features blocked by supporting v1
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2019-04-24 16:34:11 UTC - Matteo Merli: the only caveat is the naming as mentioned above
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2019-04-24 16:34:52 UTC - Matteo Merli: because of that `/` are not supported in topic names
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2019-04-24 16:36:54 UTC - Ezequiel Lovelle: great! from zk maintenance perspective there is something to consider from v1 to v2?
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2019-04-24 16:37:45 UTC - Matteo Merli: there are no breaking changes there, upgrade and rollback are still guaranteed
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2019-04-24 16:38:24 UTC - Ezequiel Lovelle: I thought that, thanks for confirming :+1:
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2019-04-24 16:44:45 UTC - Joe Francis: And the / within a topic name does not have any semantic  meaning,  No meaningful actions can be done or obserevations made by prefix grouping n with / in the "path" of a topic names.
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2019-04-24 16:45:28 UTC - Matteo Merli: I think we should have better docs around that..
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2019-04-24 17:00:43 UTC - Grant Wu: I haven’t seen any best practices/recommendations for how to use them
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2019-04-24 17:49:36 UTC - Ruud Kamphuis: <https://cl.ly/0bcc35503ee9>
<https://cl.ly/82f0308ef2eb>

Why does the dashboard say `namespace: public/functions`? While in fact, the namespace is `functions`
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2019-04-24 17:50:25 UTC - Matteo Merli: The qualified name of the namespace includes the tenant
+1 : Ruud Kamphuis
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2019-04-24 17:50:53 UTC - Matteo Merli: the structure is hierarchical tenant -&gt; namespace -&gt; topic
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2019-04-24 18:20:30 UTC - Ruud Kamphuis: There seems to be a delay in the Pulsar Dashboard before it starts showing things. As a newbie, this confuses me, because I think I did something wrong. After using Pulsar a longer time, I know I have to wait at least a minute, before it shows.
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2019-04-24 18:21:02 UTC - Ruud Kamphuis: Hope you don't mind me pointing these things out :slightly_smiling_face: It can only be better right
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2019-04-24 20:17:58 UTC - Matteo Merli: Yes, the dashboard has a collector script that runs internally and polls for the stats. That get’s executed every 1min
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2019-04-24 20:18:28 UTC - Matteo Merli: &gt; Hope you don’t mind me pointing these things out :slightly_smiling_face: It can only be better right

Of course not. These are all points that should be called out better in the docs.
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2019-04-24 20:18:35 UTC - Matteo Merli: (or improved..)
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2019-04-24 20:55:10 UTC - durga: Hi Guys - Does anyone know CorfuDB (<https://github.com/CorfuDB/CorfuDB>) and how it is different from Apache Bookkeeper?

Context: Received a request to look into CorfuDB for use as shared append-only log but it seems very much similar to Apache Bookkeeper. We already use BookKeeper. So just wondering if anyone else is familiar with CorfuDB.
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2019-04-24 20:57:06 UTC - Matteo Merli: I’ve read the Corfu paper from MS research several years ago but I’ve not followed the evolution of CorfuDb
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2019-04-25 00:34:54 UTC - daljeet: @daljeet has joined the channel
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2019-04-25 02:05:11 UTC - bilc: @bilc has joined the channel
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2019-04-25 02:20:43 UTC - yangzhijia: @yangzhijia has joined the channel
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2019-04-25 07:56:38 UTC - Romain Castagnet: Hi, I have a weird problem on my geo replication. When I produce on site 1, I can consume on site 1 and site 2. But when I produce on site 2, I can consume only on site 2. Do you have some ideas ?
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2019-04-25 09:04:56 UTC - stefan: hi, when trying to set multiple clusters for geo replication on a namespace, i end up with an Invalid cluster id. But the very same command to set up multiple clusters on the tenant works. Any idea ?
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