Is it planned to support Vert.X in Swisscom's Application Cloud? I'm thinking about a service which could be added to apps. I guess ultimately it would only need a Hazelcast service to support Vert.X, right?
You can already run non-clustered Vert.x apps on Swisscom Application cloud and there are commercial/productive apps doing so.
As you've mentioned, you would need Hazelcast for Vert.X to run in clustered mode. Hazelcast relies on TCP for communication between cluster members and this is currently not supported on Swisscom Application Cloud however this might change soon.
Moreover, there are currently no plans to offer Hazelcast as a service in the near future.
Related
I am looking at some strategies how to make bidirectional communication of applications hosted on seperate clusters. Some of them are hosted in Service Fabric and the others are in Kubernetes. One of the options is to use a DNS service on the Service Fabric and the counterpart on Kubernetes. On the other hand the Reverse Proxy seems to be a way to go. After going through the options I was thinking...what is actually the best way to create microservices that can be deployed either in SF or in K8s without worrying about the communication model which requires least changes if we wish suddenly to migrate one app from SF to K8s but still making it avaiable to the SF apps and vice versa?
I recently started to explore k8s extensions and got introduced to two concepts:
CRD.
Service catalogs.
They look pretty similar to me. The only difference to my understanding is, CRDs are deployed inside same cluster to be consumed; whereas, catalogs are deployed to be exposed outside the cluster for example as database service (client can order cluster of mysql which will be accessible from his cluster).
My query here is:
Is my understanding correct? if yes, can there be any other scenario where I would like to create catalog and not CRD.
Yes, your understanding is correct. Taken from official documentation:
Example use case
An application developer wants to use message queuing as part of their application running in a Kubernetes cluster.
However, they do not want to deal with the overhead of setting such a
service up and administering it themselves. Fortunately, there is a
cloud provider that offers message queuing as a managed service
through its service broker.
A cluster operator can setup Service Catalog and use it to communicate
with the cloud provider’s service broker to provision an instance of
the message queuing service and make it available to the application
within the Kubernetes cluster. The application developer therefore
does not need to be concerned with the implementation details or
management of the message queue. The application can simply use it as
a service.
With CRD you are responsible for provisioning resources, running backend logic and so on.
More info can be found in this KubeCon 2018 presentation.
Context
I am deploying a set of services that are containerised using Docker into AWS. No matter which deployment solution is chosen (e.g. raw EC2/ECS/Elastic Beanstalk/Fargate) we will face the issue of "service discovery".
To name just a few of the options for service discovery that I've considered:
AWS Route 53 Service Registry
Kubernetes
Hashicorp Consul
Spring Cloud Netflix Eureka
Specifics Of My Stack
I am developing Java Spring Boot applications using Spring Cloud with the target deployment environment being AWS.
Given that my stack is Spring based, spring cloud eureka made sense to me while developing locally. It was easy to set up a single node, integrates well with the stack and ecosystem of choice and required very little set up.
Locally, we are using docker compose (not swarm) to deploy services - one of the containers deployed is a single node Eureka service discovery server.
However, when we progress outside of local development and into staging or production environment we are considering options like Kubernetes.
My Own Assessment Of Pros/Cons
AWS Route 53 Service Registry
Requires us to couple code specifically to AWS services. Not a problem per se, we are quite tied in anyway on other parts of the stack (SNS/SQS).
Makes running the stack locally slightly more difficult as it relies on Route 53, I suppose we could open up a certain hosted zone for local development.
AWS native, no managing service registries or extra "moving parts".
Spring Cloud Eureka
Downside is that thus requires us to deploy and manage a high availability service registry cluster and requires more resources. Another "moving part" to manage.
Advantages are that it fits into our stack well (spring ecosystem, spring boot, spring cloud, feign and zuul work well with this). Also can be run locally trivially.
I presume we need to configure the networks and registry zone to ensure that that clients publish their host address rather and docker container internal IP address. e.g. if service A is on host A and wants to talk to service B on host B, service B needs to advertise its EC2 address rather than some internal docker IP.
Questions
If we use Kubernetes for orchestration, are there any disadvantages to using something like Spring Cloud Eureka over the built in service discovery options described here https://kubernetes.io/docs/concepts/services-networking/service/#discovering-services
Given Kube provides this, it seems suboptimal to then use eureka deployed using kube to perform discovery. I presume kube can make some optimisations that impact avaialbility and stability that might nit be possible using eureka. e.g kube would know when deploying a new service - eureka will have to rely on heartbeats/health checks and depending on how that is configured (e.g. frequency) this could result in stale records whereas i presume kube might not suffer from this for planned service shutdown/restarts. I guess it still does for unplanned failures such as a host failure or network partition.
Does anyone have any advice on this, do people use services like Kubernetes but use other mechanisms for service discovery rather than those provided by kube. Is there a good reason to do one or the other?
Possible Challenges I Anticipate
We could replace eureka, but relying on Kube to perform discovery will mean that we need to run kube locally to deploy whereas currently we have a simple tiny docker-compose file. Also, I'll have to look at how easy it'll be to ensure that ribbon, zuul and feign play nicely with this.
Currently we have ribbon configured with a eureka client so that service A can server to service B just as "service-b" for example and have ribbon resolve a healthy host via a eureka client. I guess we can configure ribbon to not use eureka and use an external Kube service name which will be resolved by Kube DNS at runtime...
Final Note
Thanks in advance for any contribution or advice. I know this might elicit a primarily opinion focused response. But I am hoping someone can provide objective guidance on when one solution might be preferable to another.
Service discovery is something you get out-of-the-box with Kubernetes. So having another external service in your platform will be another application to maintain, deploy and can be a point of failure. So I would stick with the the service discovery provided by Kubernetes.
From the Kubernetes docs:
For Kubernetes-native applications, Kubernetes offers a simple Endpoints API that is updated whenever the set of Pods in a Service changes. For non-native applications, Kubernetes offers a virtual-IP-based bridge to Services which redirects to the backend Pods.
What is the exact difference between Kubernetes-native and non-native applications?
I found the same section and interpret it as :
native are apps that are packed up and run inside k8s as some ‚kind‘. All dockerized apps should be in that category.
non native is connected with the k8s cluster infrastructure but not deployed within. A legacy app, an Oracle cluster or your backup robot may fall in this category.
From my interpretation, non-native applications are Services-without-selectors, for which end-point are not created,(such as application running in different namespace, running outside kubernetes, development databases etc.)
I have a bunch of services deploying as guest executables to service fabric and all seems fine. I was wondering if there was any point in porting the services to be native Fabric Service services.
Looking at the documentation I can't seem to find any benefits of having implementing them as such, am I missing something obvious?
If your services are stateless there is probably no compelling reason to migrate them into native stateless services. It could be different if your services were stateful; in this context I mean that they store some state inside the process.
The state in native stateful services is stored redundantly, so your services can cope with node failures. This could increase the resilience of your service. In general, you usually create native services in green field situations and rely on guest executables and containers in migration/hybrid situations.
Guest Executable is missing out on some advanced features but it is up to you to decide if you need them.
Benefits of running a guest executable in Service Fabric
There are several advantages to running a guest executable in a Service Fabric:
High availability. Applications that run in Service Fabric are made highly available. Service Fabric ensures that instances of an application are running.
Health monitoring. Service Fabric health monitoring detects if an application is running, and provides diagnostic information if there is a failure.
Application lifecycle management. Besides providing upgrades with no downtime, Service Fabric provides automatic rollback to the previous version if there is a bad health event reported during an upgrade.
Density. You can run multiple applications in a cluster, which eliminates the need for each application to run on its own hardware.
Discoverability: Using REST you can call the Service Fabric Naming service to find other services in the cluster.
I.e. There is something called Stateless Reliable Services - http://www.jamessturtevant.com/posts/Service-Fabric-Service-Types/
The above link will explain it more.