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https://issues.apache.org/jira/browse/HDDS-16179?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sreeja Chintalapati updated HDDS-16179:
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Description:
h2. Problem
Today, users can start the container balancer with {{{}ozone admin
containerbalancer start{}}}, but there is no way to preview:
* how much data needs to be moved
* how long balancing may take
* how different throttling settings affect throughput and duration
This makes it hard to plan maintenance windows or choose safe balancer settings
without trial and error.
h2. Proposed Solution
Add {{ozone admin containerbalancer dry-run}} that:
# Fetches live datanode usage from SCM
# Reads balancer limits and profile presets from the local Ozone configuration
(including {{{}ozone-site.xml{}}})
# Estimates, per profile:
** bytes to move
** per-iteration throughput
** estimated iterations
** upper-bound duration (with a +30% planning buffer)
Introduce SLOW, MEDIUM, and FAST throttling profiles with new
{{hdds.container.balancer.profile.*}} config keys for:
* max datanode involvement per iteration
* max bytes entering a target datanode
* max bytes leaving a source datanode
Add {{ContainerBalancerAdvisor}} to centralize cluster analysis, estimation,
and validation logic used by dry-run.
was:
The assessment command in HDDS-16174 tells users how much cluster imbalance
there is. The next step is estimating how long balancing will take and how many
iterations it will need — without actually moving containers or calling SCM
planning logic.
Introduce three profiles slow / medium / fast with default bandwidth caps
similar to HDFS i.e:
SLOW => 10MB/s
Medium => 100MB/s
Fast => 10GB/s
And will also have the following defaults for each profile:
Max datanode involvement cap
SLOW => 10%
Medium => 20%
Fast => 40%
Default max entering target
SLOW => 10 GB
Medium => 26 GB
Fast => 100 GB
Given the cluster summary from analyzer(HDDS-16173) and either default values
or values given by user for configs -> timeouts, balancing interval, threshold,
include/exclude nodes,
compute per profile: bytes to move, bytes to move per iteration, estimated
iterations, cycle time, and total estimated duration.
Formulas are size-based approximations — they do not simulate which containers
would move.
{code:java}
perNodeData = balancingBandwidth × moveReplicationTimeout_seconds
upperBound = min(perNodeData x sourceCount,perNodeData x
targetCount,MAX_SIZE_CEILING, BytesToMove)
maxSizeToMovePerIteration = max(containerSize + 1, upperBound)
estimatedIterations = ceil(bytesToMove / maxSizeToMovePerIteration)
iterationsWithBuffer = ceil(estimatedIterations × 1.3) // 1.3 for buffer
cycleTime = planning + moveTimeout + balancingInterval
totalTime = estimatedIterations × cycleTime
{code}
Validation: there must be at least one source and one target, bytes to move
must be positive and larger than container size, and timeout values must be
internally consistent. A balanced cluster should fail with a clear message here.
> Add logic to estimate balancer duration and iteration count
> -----------------------------------------------------------
>
> Key: HDDS-16179
> URL: https://issues.apache.org/jira/browse/HDDS-16179
> Project: Apache Ozone
> Issue Type: Sub-task
> Reporter: Sreeja Chintalapati
> Assignee: Sreeja Chintalapati
> Priority: Major
>
> h2. Problem
> Today, users can start the container balancer with {{{}ozone admin
> containerbalancer start{}}}, but there is no way to preview:
> * how much data needs to be moved
> * how long balancing may take
> * how different throttling settings affect throughput and duration
> This makes it hard to plan maintenance windows or choose safe balancer
> settings without trial and error.
> h2. Proposed Solution
> Add {{ozone admin containerbalancer dry-run}} that:
> # Fetches live datanode usage from SCM
> # Reads balancer limits and profile presets from the local Ozone
> configuration (including {{{}ozone-site.xml{}}})
> # Estimates, per profile:
> ** bytes to move
> ** per-iteration throughput
> ** estimated iterations
> ** upper-bound duration (with a +30% planning buffer)
> Introduce SLOW, MEDIUM, and FAST throttling profiles with new
> {{hdds.container.balancer.profile.*}} config keys for:
> * max datanode involvement per iteration
> * max bytes entering a target datanode
> * max bytes leaving a source datanode
> Add {{ContainerBalancerAdvisor}} to centralize cluster analysis, estimation,
> and validation logic used by dry-run.
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