Re: [akka-user] Akka Cluster with different seed node sequence

[prateek singhal]

Thanks Konrad and Patrik.

Thanks for clearing my doubt.

On Thursday, 5 October 2017 00:18:55 UTC+5:30, Patrik Nordwall wrote:
>
> Konrad is right, that is not what you want.
>
> I’d like to add two things. You don’t have to start the node listed first 
> in seed-nodes before other nodes. It’s fine to start it afterwards or at 
> the same time.
>
> Before joining itself the first seed node tries to join other seed nodes, 
> and that might be why you see it working with your setup, but it’s asking 
> for trouble and no advantage. The purpose of trying other nodes is so that 
> the first can be restarted and join existing cluster.
>
> /Patrik
> ons 4 okt. 2017 kl. 20:11 skrev Konrad “ktoso” Malawski <
> konrad@lightbend.com >:
>
>> Hi Prateek,
>> No, this is a misunderstanding of how seed-nodes work.
>>
>> The first node in that list MUST be the same node if using the seed-nodes 
>> process.
>>
>> What you did by making each node have it’s own address as the first in 
>> their seed node list is form 3 independent clusters.
>> This works as intended; The first node in this list must be the same on 
>> all nodes, only for the need of consistency of the initial cluster creation.
>>
>> A node which sees “oh, I’m the first node in the seed nodes list” will 
>> join “itself” and form the cluster.
>> This is why the first node in the list is special. The other’s order does 
>> not matter; The first one has to be the same though.
>>
>>
>> —
>> Konrad `kto.so` Malawski
>> Akka  @ Lightbend 
>>
>> On 4 October 2017 at 11:08:31, prateek singhal (prateek...@gmail.com 
>> ) wrote:
>>
>> Hi, 
>>
>> As per the documentation under cluster seed nodes (
>> https://doc.akka.io/docs/akka/2.5.4/scala/cluster-usage.html#joining-to-seed-nodes),
>>  
>> We can start seed node in any sequence, but the node configured as the 
>> first element in seed-nodes configuration list must be started when 
>> initially starting a cluster.
>>
>> In my case I have 3 servers with following seed-codes configuration
>>
>> Server A : (host1:2552)
>> akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host1:2552", 
>> "akka.tcp://ClusterSystem@host2:2552", 
>> "akka.tcp://ClusterSystem@host3:2552"]
>>
>> Server B : (host2:2552)
>> akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host2:2552", 
>> "akka.tcp://ClusterSystem@host3:2552", 
>> "akka.tcp://ClusterSystem@host1:2552"]
>>
>> Server C  : (host3:2552)
>> akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host3:2552", 
>> "akka.tcp://ClusterSystem@host1:2552", 
>> "akka.tcp://ClusterSystem@host2:2552"]
>>
>>
>> First element of seed-nodes list of each server is its own address, In 
>> this way i don't have to start particular server first when initially 
>> starting a cluster, I can start any of the 3 server of seed-node list in 
>> any order irrespective of which one is first element.
>>
>> Configuration for rest of the node in cluster:
>> Server D : (host4:2552)
>> akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host1:2552", 
>> "akka.tcp://ClusterSystem@host2:2552", 
>> "akka.tcp://ClusterSystem@host3:2552"]
>>
>> Is above configuration and understanding is correct or it will create 
>> different cluster island.
>>
>> Thanks,
>> --
>> >> Read the docs: http://akka.io/docs/
>> >> Check the FAQ: 
>> http://doc.akka.io/docs/akka/current/additional/faq.html
>> >> Search the archives: https://groups.google.com/group/akka-user
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>

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Re: [akka-user] Akka Cluster with different seed node sequence

[Patrik Nordwall]

Konrad is right, that is not what you want.

I’d like to add two things. You don’t have to start the node listed first
in seed-nodes before other nodes. It’s fine to start it afterwards or at
the same time.

Before joining itself the first seed node tries to join other seed nodes,
and that might be why you see it working with your setup, but it’s asking
for trouble and no advantage. The purpose of trying other nodes is so that
the first can be restarted and join existing cluster.

/Patrik
ons 4 okt. 2017 kl. 20:11 skrev Konrad “ktoso” Malawski <
konrad.malaw...@lightbend.com>:

> Hi Prateek,
> No, this is a misunderstanding of how seed-nodes work.
>
> The first node in that list MUST be the same node if using the seed-nodes
> process.
>
> What you did by making each node have it’s own address as the first in
> their seed node list is form 3 independent clusters.
> This works as intended; The first node in this list must be the same on
> all nodes, only for the need of consistency of the initial cluster creation.
>
> A node which sees “oh, I’m the first node in the seed nodes list” will
> join “itself” and form the cluster.
> This is why the first node in the list is special. The other’s order does
> not matter; The first one has to be the same though.
>
>
> —
> Konrad `kto.so` Malawski
> Akka  @ Lightbend 
>
> On 4 October 2017 at 11:08:31, prateek singhal (prateek.itm...@gmail.com)
> wrote:
>
> Hi,
>
> As per the documentation under cluster seed nodes (
> https://doc.akka.io/docs/akka/2.5.4/scala/cluster-usage.html#joining-to-seed-nodes),
> We can start seed node in any sequence, but the node configured as the
> first element in seed-nodes configuration list must be started when
> initially starting a cluster.
>
> In my case I have 3 servers with following seed-codes configuration
>
> Server A : (host1:2552)
> akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host1:2552",
> "akka.tcp://ClusterSystem@host2:2552", "akka.tcp://ClusterSystem@host3
> :2552"]
>
> Server B : (host2:2552)
> akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host2:2552",
> "akka.tcp://ClusterSystem@host3:2552", "akka.tcp://ClusterSystem@host1
> :2552"]
>
> Server C  : (host3:2552)
> akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host3:2552",
> "akka.tcp://ClusterSystem@host1:2552", "akka.tcp://ClusterSystem@host2
> :2552"]
>
>
> First element of seed-nodes list of each server is its own address, In
> this way i don't have to start particular server first when initially
> starting a cluster, I can start any of the 3 server of seed-node list in
> any order irrespective of which one is first element.
>
> Configuration for rest of the node in cluster:
> Server D : (host4:2552)
> akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host1:2552",
> "akka.tcp://ClusterSystem@host2:2552", "akka.tcp://ClusterSystem@host3
> :2552"]
>
> Is above configuration and understanding is correct or it will create
> different cluster island.
>
> Thanks,
> --
> >> Read the docs: http://akka.io/docs/
> >> Check the FAQ:
> http://doc.akka.io/docs/akka/current/additional/faq.html
> >> Search the archives: https://groups.google.com/group/akka-user
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>
> --
> >> Read the docs: http://akka.io/docs/
> >> Check the FAQ:
> http://doc.akka.io/docs/akka/current/additional/faq.html
> >> Search the archives: https://groups.google.com/group/akka-user
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Re: [akka-user] Akka Cluster with different seed node sequence

[Konrad “ktoso” Malawski]

Hi Prateek,
No, this is a misunderstanding of how seed-nodes work.

The first node in that list MUST be the same node if using the seed-nodes
process.

What you did by making each node have it’s own address as the first in
their seed node list is form 3 independent clusters.
This works as intended; The first node in this list must be the same on all
nodes, only for the need of consistency of the initial cluster creation.

A node which sees “oh, I’m the first node in the seed nodes list” will join
“itself” and form the cluster.
This is why the first node in the list is special. The other’s order does
not matter; The first one has to be the same though.


—
Konrad `kto.so` Malawski
Akka  @ Lightbend 

On 4 October 2017 at 11:08:31, prateek singhal (prateek.itm...@gmail.com)
wrote:

Hi,

As per the documentation under cluster seed nodes (https://doc.akka.io/docs/
akka/2.5.4/scala/cluster-usage.html#joining-to-seed-nodes), We can start
seed node in any sequence, but the node configured as the first element in
seed-nodes configuration list must be started when initially starting a
cluster.

In my case I have 3 servers with following seed-codes configuration

Server A : (host1:2552)
akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host1:2552",
"akka.tcp://ClusterSystem@host2:2552", "akka.tcp://ClusterSystem@host3:2552"
]

Server B : (host2:2552)
akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host2:2552",
"akka.tcp://ClusterSystem@host3:2552", "akka.tcp://ClusterSystem@host1:2552"
]

Server C  : (host3:2552)
akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host3:2552",
"akka.tcp://ClusterSystem@host1:2552", "akka.tcp://ClusterSystem@host2:2552"
]


First element of seed-nodes list of each server is its own address, In this
way i don't have to start particular server first when initially starting a
cluster, I can start any of the 3 server of seed-node list in any order
irrespective of which one is first element.

Configuration for rest of the node in cluster:
Server D : (host4:2552)
akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host1:2552",
"akka.tcp://ClusterSystem@host2:2552", "akka.tcp://ClusterSystem@host3:2552"
]

Is above configuration and understanding is correct or it will create
different cluster island.

Thanks,
--
>> Read the docs: http://akka.io/docs/
>> Check the FAQ:
http://doc.akka.io/docs/akka/current/additional/faq.html
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>>  Check the FAQ: 
>> http://doc.akka.io/docs/akka/current/additional/faq.html
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[akka-user] Akka Cluster with different seed node sequence

[prateek singhal]

Hi,

As per the documentation under cluster seed nodes (
https://doc.akka.io/docs/akka/2.5.4/scala/cluster-usage.html#joining-to-seed-nodes),
 
We can start seed node in any sequence, but the node configured as the 
first element in seed-nodes configuration list must be started when 
initially starting a cluster.

In my case I have 3 servers with following seed-codes configuration

Server A : (host1:2552)
akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host1:2552", 
"akka.tcp://ClusterSystem@host2:2552", "akka.tcp://ClusterSystem@host3:2552"
]

Server B : (host2:2552)
akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host2:2552", 
"akka.tcp://ClusterSystem@host3:2552", "akka.tcp://ClusterSystem@host1:2552"
]

Server C  : (host3:2552)
akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host3:2552", 
"akka.tcp://ClusterSystem@host1:2552", "akka.tcp://ClusterSystem@host2:2552"
]


First element of seed-nodes list of each server is its own address, In this 
way i don't have to start particular server first when initially starting a 
cluster, I can start any of the 3 server of seed-node list in any order 
irrespective of which one is first element.

Configuration for rest of the node in cluster:
Server D : (host4:2552)
akka.cluster.seed-nodes = ["akka.tcp://ClusterSystem@host1:2552", 
"akka.tcp://ClusterSystem@host2:2552", "akka.tcp://ClusterSystem@host3:2552"
]

Is above configuration and understanding is correct or it will create 
different cluster island.

Thanks,

-- 
>>  Read the docs: http://akka.io/docs/
>>  Check the FAQ: 
>> http://doc.akka.io/docs/akka/current/additional/faq.html
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