Ratnakar Malla

Generalist - Security & Performance Architect

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Resolving ‘Node(s) had no available volume zone’ Errors in Kubernetes

Introduction:

In Kubernetes, a volume zone is a specific location where a volume is stored. It is used to ensure that volumes are stored in a specific location, such as an availability zone in a cloud provider. However, sometimes you may encounter an error message that says “Node(s) had no available volume zone”. This error message indicates that a node does not have a volume zone available to schedule a pod.

In this blog post, we will explore the causes of this error message and provide some solutions to resolve it.

Causes of the error:

There are several reasons why a node may not have a volume zone available:

  • The node is not configured with a volume zone
  • The volume zone is not available due to a lack of resources (e.g., disk space)
  • The volume zone is not properly configured
  • The node is not in the same availability zone as the volume

Solutions:

To resolve the “Node(s) had no...

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Installing Hue on HDP 2.1

When installing Hue on Hadoop Data Platform from Horton Works, you might run into issue compiling the code.
Maven fails with the following stack trace:

cd hue-3.8.1/desktop/libs/hadoop/java && mvn clean install -DskipTests

Jul 13, 2015 10:49:26 p.m. com.google.inject.internal.MessageProcessor visit

INFO: An exception was caught and reported. Message: java.util.NoSuchElementException

java.util.NoSuchElementException

at java.util.AbstractList$1.next(libgcj.so.10)

at com.google.inject.spi.InjectionPoint.forMember(InjectionPoint.java:116)

at com.google.inject.spi.InjectionPoint.(InjectionPoint.java:73)

at com.google.inject.spi.InjectionPoint$InjectableMethod.toInjectionPoint(InjectionPoint.java:459)

at com.google.inject.spi.InjectionPoint.getInjectionPoints(InjectionPoint.java:725)

at com.google.inject.spi.InjectionPoint.forInstanceMethodsAndFields(InjectionPoint.java:358)

at...

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Solving performance problems on Java web applications - Our experiences

This material is from my presentation at Silicon Valley Code Camp - 2014
svcc-2014-presentation.PNG

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Trouble with EhCache

We are running EhCache in production, and the cache has been configured with Cache size in memory and on the disk.
However, upon analysis of heap dump using Eclipse Memory Analysis Tool (MAT), we noticed the EhCache was using almost 80% of the memory.

Heap Snapshot

Further research of EhCache , and reading forums, we noticed that the open source version of EhCache was a crippleware, with a serious limitation.
Here is what I read from EhCache forums:

*As you have noticed the open-source disk stores do not store the entire cache on disk. Instead the values are stored on the disk, and the keys are stored in memory mapped to value objects which reference where on disk the associated value object can be found. This means each on-disk mapping has an associated in-memory overhead equal to it’s key-size plus a fixed overhead per mapping. *

Ref: EhCache Forum Post

In conclusion it is very important...

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