I'm using Hystrix within Weblogic Application Server. I’m trying to provide Hystrix an external executor service (javax.enterprise.concurrent.ManagedExecutorService to be exact). This executor service is provided and managed by WAS.
Is possible to provide external executor service to Hystrix? Or maybe it’s against Hystrix policy and executor service MUST be provided and managed by Hystrix itself?
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I've an API (python-flask app) running on an app service in azure and want to implement a queuing system using Azure Service Bus such that requests from API are sent to a simple FIFO queue managed/ran by the service bus. Another resource in Azure will be pulling from this queue and running the jobs based on the contents of the json/payload contained in the message in the queue element.
When this element has been processed by the other resource I want to encode the job status/metadata (e.g., "finished" along with metadata such as the location where resulting data was stored). I read about such a system that makes use of the lightweight database offered by Redis, however, I'm wondering if something like this lightweight database/cache system of job status/ids/metadata is available through Azure Service Bus? I'm aware that Redis can be run standalone on a VM in Azure, however, if this can all be managed via the service bus that would be ideal. I couldn't find specifics on this being offered within Azure Service Bus and due to how this job metadata is later being accessed I cannot just push metadata messages to a new queue.
Does anyone have any insight on this or potential alternatives? If Redis can be run alongside flask within the same App Service then that would be ideal, but again I wasn't able to find anything explicit on this and it doesn't seem possible to simultaneously run a flask server/app and Redis server at the same time on an App Service.
Thanks.
I'm wondering if something like this lightweight database/cache system
of job status/ids/metadata is available through Azure Service Bus?
Azure Service Bus is a fully managed enterprise message broker, Azure Redis is a NoSQL database with steroids. It also offers queue mechanism and some other data structures.
it doesn't seem possible to simultaneously run a flask server/app and
Redis server at the same time on an App Service.
You can, but inside containers.
Please check if this can help you: https://stackoverflow.com/a/39008342/1384539
From whatever i read, i could not find a way to connect to master node in Azure kubernetes Service. I have a requirement to read some parameters like 'enable-admission-plugins' which is possible from master node. Is there any third party api available to get this info.
More specific i need to read the files 'kube-apiserver.yaml', 'kube-controller-manager.yaml'
No, this is not possible. Masters are managed by Microsoft and you dont have access to them. All the configurations are to be done through the AKS api (mostly when you create it).
Azure Kubernetes Service (AKS) makes it simple to deploy a managed
Kubernetes cluster in Azure. AKS reduces the complexity and
operational overhead of managing Kubernetes by offloading much of that
responsibility to Azure. As a hosted Kubernetes service, Azure handles
critical tasks like health monitoring and maintenance for you. The
Kubernetes masters are managed by Azure. You only manage and maintain
the agent nodes.
I'm submitting Java runnables to hazelcast executor service, the runnables need access to specific business objects and also to hazelcast client.
Is there any way to deploy a hazelcast cluster on hazelcast cloud with specific dependencies?
#newlogic, according to Hazelcast Cloud Documentation, User Code Deployment feature is enabled. All you need to do is to enable it on the client as well & configure it, as documented here: https://docs.hazelcast.org/docs/latest/manual/html-single/index.html#client-user-code-deployment-beta
we installed the follwing presto cluster on Linux redhat 7.2 version
presto latest version - 0.216
1 presto coordinator
231 presto workers
on each worker machine we can use the follwing command in order to verify the status
/app/presto/presto-server-0.216/bin/launcher status
Running as 61824
and also stop/start as the follwing
/app/presto/presto-server-0.216/bin/launcher stop
/app/presto/presto-server-0.216/bin/launcher start
I also searches in google about UI that can manage the presto status/stop/start
but not seen any thing about this
its very strange that presto not comes with some user interface that can show the cluster status and do stop/start action if we need to do so
as all know the only user interface of presto is show status and not have the actions as stop/start
in the above example screen we can see that the active presto worker are only 5 from 231 , but this UI not support stop/start actions and not show on which worker presto isn't active
so what we can do about it?
its very bad idea to access each worker machine and see if presto is up or down
why presto not have centralized UI that can do stop/start action ?
example what we are expecting from the UI , - partial list
.
.
.
Presto currently uses discovery service where workers announce themselves to join the cluster, so if a worker node is not registered there is no way for coordinator or discovery server to know about its presence and/or restart it.
At Qubole, we use an external service alongside presto master that tracks nodes which do not register with discovery service within a certain interval. This service is responsible for removing such nodes from the cluster.
One more thing we do is use monit service on each of presto worker nodes, which ensures that presto server is restarted whenever it goes down.
You may have to do something similar for cluster management , as presto does not provide it right now.
In my opinion and experience managing prestosql cluster, it matters of service discovery in architecture patterns.
So far, it uses following patterns in the open source release of prestodb/prestosql:
server-side service discovery - it means a client app like presto cli or any app uses presto sdk just need to reach a coordinator w/o awareness of worker nodes.
service registry - a place to keep tracking available instances.
self-registration - A service instance is responsible for registering itself with the service registry. This is the key part that it forces several behaviors:
Service instances must be registered with the service registry on startup and unregistered on shutdown
Service instances that crash must be unregistered from the service registry
Service instances that are running but incapable of handling requests must be unregistered from the service registry
So it keeps the life-cycle management of each presto worker to each instance itself.
so what we can do about it?
It provides some observability from presto cluster itself like HTTP API /v1/node and /v1/service/presto to see instance status. Personally I recommend using another cluster manager like k8s or nomad to manage presto cluster members.
its very bad idea to access each worker machine and see if presto is up or down
why presto not have centralized UI that can do stop/start action ?
No opinion on good/bad. Take k8s for example, you can manage all presto workers as one k8s deployment and manage each presto worker in one pod. It can use Liveness, Readiness and Startup Probes to automate the instance lifecycle with a few YAML code. E.g., the design of livenessProbe of helm chart stable/presto. And cluster manageer like k8s does provide web UI so that you can touch resources to act like an admin. . Or you can choose to write more Java code to extend Presto.
I was looking for configure the thread pool by application instead of profile. Basically, to avoid the unavailability of threads for most important application that share the profile with application that can run in background.
Is there any configuration thread pools by application instead of profile?
The best would be to use a dedicated thread pool for the critical application.
However in order to achieve that you need to use a separate host-port combination for that particular application.
That is because a web threads pool is associated with a web container transport chain and a transport chain is determined by a host-port pair.