Flink Exception - assigned slot container was removed

[Flink Developer]

Hi, I have a Flink application sourcing from a topic in Kafka (400 partitions) and sinking to S3 using bucketingsink and using RocksDb for checkpointing every 2 mins. The Flink app runs with parallelism 400 so that each worker handles a partition. This is using Flink 1.5.2. The Flink cluster uses 10 task managers with 40 slots each.

After running for a few days straight, it encounters a Flink exception:

Org.apache.flink.util.FlinkException: The assigned slot container_1234567_0003_01_000009_1 was removed.

This causes the Flink job to fail. It is odd to me. I am unsure what causes this. Also, during this time, I see some checkpoints stating "checkpoint was declined (tasks not ready)". At this point, the job is unable to recover and fails. Does this happen if a slot or worker is not doing processing for X amount of time? Would I need to increase the Flink config properties for the following when creating the Flink cluster in yarn?

Slot.idle.timeout

Slot.request.timeout

Web.timeout

Heartbeat.interval

Heartbeat.timeout

Any help would be greatly appreciated.

[罗齐]

Hi,

It looks that some of your slots were freed during the job execution (possibly due to idle for too long). AFAIK the exception was thrown when a pending Slot request was removed. You can try increase the “Slot.idle.timeout” to mitigate this issue (default is 50000, try 3600000 or higher).

Regards,

Qi

On Nov 26, 2018, at 7:36 AM, Flink Developer <[hidden email]> wrote:

Hi, I have a Flink application sourcing from a topic in Kafka (400 partitions) and sinking to S3 using bucketingsink and using RocksDb for checkpointing every 2 mins. The Flink app runs with parallelism 400 so that each worker handles a partition. This is using Flink 1.5.2. The Flink cluster uses 10 task managers with 40 slots each.

After running for a few days straight, it encounters a Flink exception:

Org.apache.flink.util.FlinkException: The assigned slot container_1234567_0003_01_000009_1 was removed.

This causes the Flink job to fail. It is odd to me. I am unsure what causes this. Also, during this time, I see some checkpoints stating "checkpoint was declined (tasks not ready)". At this point, the job is unable to recover and fails. Does this happen if a slot or worker is not doing processing for X amount of time? Would I need to increase the Flink config properties for the following when creating the Flink cluster in yarn?

Slot.idle.timeout

Slot.request.timeout

Web.timeout

Heartbeat.interval

Heartbeat.timeout

Any help would be greatly appreciated.

[Flink Developer]

Thanks for the suggestion Qi. I tried increasing slot.idle.timeout to 3600000 but it seems to still have encountered the issue. Does this mean if a slot or "flink worker" has not processed items for 1 hour, that it will be removed?

Would any other flink configuration properties help for this?

slot.request.timeout

web.timeout

heartbeat.interval

heartbeat.timeout

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Sunday, November 25, 2018 6:56 PM, 罗齐 <[hidden email]> wrote:

Hi,

It looks that some of your slots were freed during the job execution (possibly due to idle for too long). AFAIK the exception was thrown when a pending Slot request was removed. You can try increase the “Slot.idle.timeout” to mitigate this issue (default is 50000, try 3600000 or higher).

Regards,

Qi

On Nov 26, 2018, at 7:36 AM, Flink Developer <[hidden email]> wrote:

Hi, I have a Flink application sourcing from a topic in Kafka (400 partitions) and sinking to S3 using bucketingsink and using RocksDb for checkpointing every 2 mins. The Flink app runs with parallelism 400 so that each worker handles a partition. This is using Flink 1.5.2. The Flink cluster uses 10 task managers with 40 slots each.

After running for a few days straight, it encounters a Flink exception:

Org.apache.flink.util.FlinkException: The assigned slot container_1234567_0003_01_000009_1 was removed.

This causes the Flink job to fail. It is odd to me. I am unsure what causes this. Also, during this time, I see some checkpoints stating "checkpoint was declined (tasks not ready)". At this point, the job is unable to recover and fails. Does this happen if a slot or worker is not doing processing for X amount of time? Would I need to increase the Flink config properties for the following when creating the Flink cluster in yarn?

Slot.idle.timeout

Slot.request.timeout

Web.timeout

Heartbeat.interval

Heartbeat.timeout

Any help would be greatly appreciated.

[Flink Developer]

In addition, after the Flink job has failed from the above exception, the Flink job is unable to recover from previous checkpoint. Is this the expected behavior? How can the job be recovered successfully from this?

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Monday, November 26, 2018 12:30 AM, Flink Developer <[hidden email]> wrote:

Thanks for the suggestion Qi. I tried increasing slot.idle.timeout to 3600000 but it seems to still have encountered the issue. Does this mean if a slot or "flink worker" has not processed items for 1 hour, that it will be removed?

Would any other flink configuration properties help for this?

slot.request.timeout

web.timeout

heartbeat.interval

heartbeat.timeout

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Sunday, November 25, 2018 6:56 PM, 罗齐 <[hidden email]> wrote:

Hi,

It looks that some of your slots were freed during the job execution (possibly due to idle for too long). AFAIK the exception was thrown when a pending Slot request was removed. You can try increase the “Slot.idle.timeout” to mitigate this issue (default is 50000, try 3600000 or higher).

Regards,

Qi

On Nov 26, 2018, at 7:36 AM, Flink Developer <[hidden email]> wrote:

Hi, I have a Flink application sourcing from a topic in Kafka (400 partitions) and sinking to S3 using bucketingsink and using RocksDb for checkpointing every 2 mins. The Flink app runs with parallelism 400 so that each worker handles a partition. This is using Flink 1.5.2. The Flink cluster uses 10 task managers with 40 slots each.

After running for a few days straight, it encounters a Flink exception:

Org.apache.flink.util.FlinkException: The assigned slot container_1234567_0003_01_000009_1 was removed.

This causes the Flink job to fail. It is odd to me. I am unsure what causes this. Also, during this time, I see some checkpoints stating "checkpoint was declined (tasks not ready)". At this point, the job is unable to recover and fails. Does this happen if a slot or worker is not doing processing for X amount of time? Would I need to increase the Flink config properties for the following when creating the Flink cluster in yarn?

Slot.idle.timeout

Slot.request.timeout

Web.timeout

Heartbeat.interval

Heartbeat.timeout

Any help would be greatly appreciated.

[qi luo]

This is weird. Could you paste your entire exception trace here?

On Nov 26, 2018, at 4:37 PM, Flink Developer <[hidden email]> wrote:

In addition, after the Flink job has failed from the above exception, the Flink job is unable to recover from previous checkpoint. Is this the expected behavior? How can the job be recovered successfully from this?

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Monday, November 26, 2018 12:30 AM, Flink Developer <[hidden email]> wrote:

Thanks for the suggestion Qi. I tried increasing slot.idle.timeout to 3600000 but it seems to still have encountered the issue. Does this mean if a slot or "flink worker" has not processed items for 1 hour, that it will be removed?

Would any other flink configuration properties help for this?

slot.request.timeout

web.timeout

heartbeat.interval

heartbeat.timeout

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Sunday, November 25, 2018 6:56 PM, 罗齐 <[hidden email]> wrote:

Hi,

It looks that some of your slots were freed during the job execution (possibly due to idle for too long). AFAIK the exception was thrown when a pending Slot request was removed. You can try increase the “Slot.idle.timeout” to mitigate this issue (default is 50000, try 3600000 or higher).

Regards,

Qi

On Nov 26, 2018, at 7:36 AM, Flink Developer <[hidden email]> wrote:

Hi, I have a Flink application sourcing from a topic in Kafka (400 partitions) and sinking to S3 using bucketingsink and using RocksDb for checkpointing every 2 mins. The Flink app runs with parallelism 400 so that each worker handles a partition. This is using Flink 1.5.2. The Flink cluster uses 10 task managers with 40 slots each.

After running for a few days straight, it encounters a Flink exception:

Org.apache.flink.util.FlinkException: The assigned slot container_1234567_0003_01_000009_1 was removed.

This causes the Flink job to fail. It is odd to me. I am unsure what causes this. Also, during this time, I see some checkpoints stating "checkpoint was declined (tasks not ready)". At this point, the job is unable to recover and fails. Does this happen if a slot or worker is not doing processing for X amount of time? Would I need to increase the Flink config properties for the following when creating the Flink cluster in yarn?

Slot.idle.timeout

Slot.request.timeout

Web.timeout

Heartbeat.interval

Heartbeat.timeout

Any help would be greatly appreciated.

[Andrey Zagrebin]

Hi

It can be also that some task managers fail, then pending checkpoints are declined and slots are removed.

Can you also have a look into task managers logs?

Best,

Andrey

On 26 Nov 2018, at 12:19, qi luo <[hidden email]> wrote:

This is weird. Could you paste your entire exception trace here?

On Nov 26, 2018, at 4:37 PM, Flink Developer <[hidden email]> wrote:

In addition, after the Flink job has failed from the above exception, the Flink job is unable to recover from previous checkpoint. Is this the expected behavior? How can the job be recovered successfully from this?

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Monday, November 26, 2018 12:30 AM, Flink Developer <[hidden email]> wrote:

Thanks for the suggestion Qi. I tried increasing slot.idle.timeout to 3600000 but it seems to still have encountered the issue. Does this mean if a slot or "flink worker" has not processed items for 1 hour, that it will be removed?

Would any other flink configuration properties help for this?

slot.request.timeout

web.timeout

heartbeat.interval

heartbeat.timeout

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Sunday, November 25, 2018 6:56 PM, 罗齐 <[hidden email]> wrote:

Hi,

It looks that some of your slots were freed during the job execution (possibly due to idle for too long). AFAIK the exception was thrown when a pending Slot request was removed. You can try increase the “Slot.idle.timeout” to mitigate this issue (default is 50000, try 3600000 or higher).

Regards,

Qi

On Nov 26, 2018, at 7:36 AM, Flink Developer <[hidden email]> wrote:

Hi, I have a Flink application sourcing from a topic in Kafka (400 partitions) and sinking to S3 using bucketingsink and using RocksDb for checkpointing every 2 mins. The Flink app runs with parallelism 400 so that each worker handles a partition. This is using Flink 1.5.2. The Flink cluster uses 10 task managers with 40 slots each.

After running for a few days straight, it encounters a Flink exception:

Org.apache.flink.util.FlinkException: The assigned slot container_1234567_0003_01_000009_1 was removed.

This causes the Flink job to fail. It is odd to me. I am unsure what causes this. Also, during this time, I see some checkpoints stating "checkpoint was declined (tasks not ready)". At this point, the job is unable to recover and fails. Does this happen if a slot or worker is not doing processing for X amount of time? Would I need to increase the Flink config properties for the following when creating the Flink cluster in yarn?

Slot.idle.timeout

Slot.request.timeout

Web.timeout

Heartbeat.interval

Heartbeat.timeout

Any help would be greatly appreciated.