We have a use case to monitor kubernetes clusters and I am trying to find the list of exceptions thrown by kubernetes to reflect the status of the k8s server (in a namespace) while trying to submit a job on the UI.
Example: if k8s server throws ClusterNotFound exception that means we cannot submit any more jobs to that api server.
Is there such a comprehensive list?
I came across this in Go Lang. Will this be it? Does java has something like this?
The file you are referencing is a part of Kubernetes library used by many Kubernetes components for API requests fields validations. As all Kubernetes components are written in Go and I couldn't find any plans to port Kubernetes to Java, it's unlikely to have a Java version of that file.
However, there is an officially supported Kubernetes client library, written in Java, so you can check for the proper modules to validate API requests and process API responses in the java-client repostiory or on the javadoc site.
For example, objects that are used to contain proper or improper HTTP replies from Kubernetes apiserver: V1Status and ApiExceptions, (repository link)
Please consider to check java-client usage examples for better understanding.
Detailed Kubernetes RESTful API reference could be found on the official page
For example: Deployment create request
If you are really interested in Kubernetes cluster monitoring and logging aspects, please consider to read the following articles at the beginning:
Metrics For Kubernetes System Components
Kubernetes Control Plane monitoring with Datadog
How to monitor Kubernetes control plane
Logging Architecture
A Practical Guide to Kubernetes Logging
I am new to OpenShift so apologies in advance if this question is not very clear.
I have a project starting in Openshift and will use the Elasticsearch provided docker image as a data store.
ElasiticSearch is bound only to local host by default when installed, and if I was running app on a server I would keep this configuration so as not to expose ElasticSearch interface as connectivity only required by the application, no need to expose outside of project.
If I make a route for Elasticsearch without changing it's default config, it is accessible to other Pods in project but also outside of the project, like the main application. Is it possible to make a route that is internal to the project only so that Elasticsearch interface is not accessible outside of the project or by other means ? Or a way to have a common local host address between pods/applications ?
I tried to group the services but still not available.
Any support to put me in right direction really appreciated.
I'm trying to run a web application of "hello world" complexity on Elastic Beanstalk. I have no problem doing this with Spring Boot on Elastic Beanstalk.
But when I try to use Spring Cloud AWS, I encounter a myriad of problems. The reference guide never mentions that running on Beanstalk is possible, so perhaps I am barking up the wrong tree?
The root problem I seem to encounter is the stackResourceRegistryFactoryBean blowing up when trying to identify the "stack" being used - i.e. the CloudFormation stack. But I'm using Elastic Beanstalk, not CloudFormation. The root exception is:
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.aws.core.env.stack.config.StackResourceRegistryFactoryBean]: Factory method 'stackResourceRegistryFactoryBean' threw exception; nested exception is java.lang.IllegalAccessError: tried to access class org.springframework.cloud.aws.core.env.stack.config.AutoDetectingStackNameProvider from class org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588)
... 89 more
Caused by: java.lang.IllegalAccessError: tried to access class org.springframework.cloud.aws.core.env.stack.config.AutoDetectingStackNameProvider from class org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration
at org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration.stackResourceRegistryFactoryBean(ContextStackAutoConfiguration.java:71)
at org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration$$EnhancerBySpringCGLIB$$432c7658.CGLIB$stackResourceRegistryFactoryBean$0(<generated>)
at org.springframework.cloud.aws.autoconfigure.context.ContextStackAutoConfiguration$StackAutoDetectConfiguration$$EnhancerBySpringCGLIB$$432c7658$$FastClassBySpringCGLIB$$47c6e7d2.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
...
There are tags present on the generated EC2 instance for "aws:cloudformation:stack-id" and "aws:cloudformation:stack-name" if it is relevant, and my understanding is that Beanstalk uses CloudFormation stacks behind the scenes. I've tried manually specifying the name of the stack via #EnableStackConfiguration, but since the name is generated I'd rather not do this, even if it did work.
So my questions are:
1) Is it possible to run a Spring Cloud AWS-based application on Elastic Beanstalk?
2) If so, are there any special steps required? For example, I already discovered the one about CloudFormation read access being required on the role.
3) Is there a way to disable the part of Spring Cloud AWS that attempts to obtain resource names from the stack? At this point my app doesn't need this.
thanks in advance,
k
Ok, so over time I've answered my own questions on this topic.
First, Elastic Beanstalk uses CloudFormation behind the scenes, so this is why there is a "stack".
Next, Spring Cloud AWS tries to make connections to DBs and such easier by binding to other resources that may have been created in the same stack. This is reasonable - if you are expecting it. If not, as #barthand says, it is probably better to turn this feature off with cloud.aws.stack.auto=false than have the app fail to start up.
Third, When using Elastic Beanstalk, you have the opportunity to associate an execution role with your instance - otherwise the code in your instance isn't able to do much of anything with the AWS SDK. To explore the resources in a CloudFormation stack, Spring Cloud AWS tries to make some API calls, and by default these are not allowed. To make them allowed, I added these permissions to the role:
"Statement": [
{
"Effect": "Allow",
"Action": [
"cloudformation:DescribeStacks",
"cloudformation:DescribeStackEvents",
"cloudformation:DescribeStackResource",
"cloudformation:DescribeStackResources",
"cloudformation:GetTemplate",
"cloudformation:List*"
],
"Resource": "*"
}
]
So to answer my original questions:
Yes it is definitely possible (and easy!) to run a Spring Cloud AWS
program in Elastic Beanstalk.
Special requirements - Need to open the permissions on the associated role to include CloudFormation read operations, or...
Disable these using cloud.aws.stack.auto=false
Hope this info helps someone in the future
spring-cloud-aws seems to assume by default that you're running your app using your custom CloudFormation template.
In case of Elastic Beanstalk, you simply need to tell spring-cloud-aws to resign from obtaining information about the stack automatically:
cloud.aws.stack.auto = false
Not sure why it is not mentioned in the docs. For basic Java apps, Elastic Beanstalk seems to be an obvious choice.
I am using Node-RED on IBM Bluemix. I am trying to connect to MySQL hosted by ClearDB, but I cannot find a suitable node in the database category.
How can I bind to existing ClearDB service that I already have bound to another app?
You can take a look at this MySQL node for Node-RED in the flow and node library, it is an extension. The steps to add additional node types to the editor is explained in the Node-RED documentation in general, however it does not directly apply to Bluemix. For your Bluemix environment you would need to access and modify the environment. See this post on how to deploy your customized Node-RED environment to Bluemix.
Is there a way for my application to access the labels assigned to the pod / service during runtime?
Either via client API or via ENV / passed variables to the docker container?
The Downward API is designed to automatically expose information about the pod's configuration to the pod using environment variables. As of Kubernetes 1.0 is only exposes the pod's name and namespace. Adding labels to the Downward API is being discussed in #560 but isn't currently implemented.
In the mean time, your application can query the Kubernetes apiserver and introspect it's configuration to determine what labels have been set.