I am developing an IoT application (it controls EnOcean devices). I have N servers controlling the devices and one management application, which manages and configures the devices associated with each server.
The servers are basically identical, but hold different device data. Their basic functionality is configured in Maven: I don't expect to reconfigure from Karaf's command line.
Is this an appropriate application for Karaf Cellar? I can see that Cellar would help with the configuration of the N servers, but can I include the management app in the same cluster? Or is the Cellar philosophy more that the management function should also be replicated across all N servers?
Karaf Cellar usually does a full replication for all nodes within one group. So what you could do is, create two different types of groups. One group containing your N servers, while the other group has only one "Management" node with it.
For communication across group boundaries, use the Cellar Distributed OSGi. That way you can have specific services located in one group as providing services while the consumer can be in the other one.
In future please ask at the karaf users mailinglist, as it has much more people answering :-)
Related
I have a question about Service Layer(SL):
can I build cluster with several SL servers to load scaling?
Where can I read about it?
Technically you can create all the servesr with any number of server instances (service layers) you want - all running on the same database. That will work just fine.
However there is no built-in load balancing so you would have to handle that on your own.
The most common way of doing this is simply by providing different shortcuts to different groups of users. Each shortcut is linked to their own server instance and thus the users are directed to different servers.
I am using a Fabric 2.2 network with two organizations, one endorsing peer per organization and one ordering service.
I want to scale up my network with many clients and servers in order to test the performance of the system (latency and throughput), similarly to what it is done in this paper ieeexplore.ieee.org/iel7/69/4358933/08246573.pdf in section 6.1.2
I confuse maybe the terms. I am really new to Fabric.
What is the meaning of "clients" and "servers" in the paper? Are they ca-servers and ca-clients? In this case, how to configure a network with an increasing number of Fabric clients and servers?
My company has a .NET project which serves following use cases
It listens on a WebSocket Port with certificate based client authentication.
It listens on another WebSocket Port with authorization header based client authentication.
It listens on a TCP Port with certificate based client authentication.
On the above three ports different set of client devices are connected.
Now my company wants to convert this application in .NET Core so that this can be deployed on Linux servers to save the deployment cost. As an architect I am thinking in the direction of adopting microservices architecture along with migrating the application in .NET Core. So I am thinking that the above application can be break down into three microservices based on the above use cases.
AFAIK microservices architecture means breaking down your application into smaller services which serves a particular use case. So breaking this complete application into three different microservices is correct or not.
My organization is very new to micro services architecture.I just want to know that whether this thinking is correct or not as per architecture.
Thanks in advance for your help.
Generally I'd try to break things down based on business domains (or business capabilities) instead of technical reasons.
A good place to start might be reading about domain driven design and bounded contexts - see here - there's some good further reading at the end of that link.
Yes you are thinking in right direction.
Here are my suggestion-
you should go for .NET Core and Docker for implementing your Microservices in a better way.
There can be multiple cases when you will go for docker container in this scenario-
1: Run the same image in multiple containers
2: Manage different Containers
3: Run the same image in multiple environments
4: Tag and Run image with different versions
And other reason to go for micro services with docker-
Microservices are smaller in size
Microservices are easier to develop, deploy, and debug, because a fix only needs to be deployed onto the microservice with the bug, instead of across the board
Microservices can be scaled quickly and can be reused among different projects
Microservices work well with containers like Docker
Microservices are independent of each other, meaning that if one of the microservices goes down, there is little risk of the full application shutting down.
You do more research on the same and easily go for micro services architecture.
This may not be answering your question, but I thought it could be useful, especially in light of the fact that your organization is very new to micro-services.
I would recommend to carefully evaluate the advantages and especially disadvantages (complexity) that micro-services architecture introduces.
Just a few examples of things that you will need to think about are log aggregation, communication between services (sync vs async), E2E and integration tests, eventual consistency, etc. Obviously you may end up not having to deal with some of these, but all of them do become a lot more complicated with micro-services.
There should be good business justification to take on the additional complexity (=cost).
Microservices shouldn't be measured on how small enough but how autonomous and independent they are. Microservices are great to be designed around business and domain context and mentioned in details Identifying domain boundires
Since you are starting to build microservices in .Net core why not consider severless microservices ? You have plenty on options in major clouds (AWS,Azure) to build serverless microservices. Serverless are quicker to build and you get generous free tier and you don't have to manage clusters. Is there specific reason you would want to use Kubernetes? you can read more about cloud native and servlerss here Design Cloud native and Serverless
I just saw the Realm Mobile Platform. I'm curious what kind of redundancy is available outside of users having a full backup locally.
Can you have multiple Realm Object Servers?
It is possible to run multiple Realm Object Servers in various configurations for greater performance or reliability. This advanced functionality is part of the Enterprise Edition.
For the Developer Edition, you can run multiple Realm Object Servers but they all act independent of each other. For example you could split you user data across multiple servers with certain user groups using specific machines.
I am working on a new project with Kubernetes and I need three environments: DEV,QA and PROD.
What is most recommended, create Multiple Clusters or create one big cluster separating environments by namespace.
Are you just going to have a single prod cluster or multiple prod clusters? One thing to consider is that updating the cluster management software (to a new k8s release) can impact your application. If you only plan to have a single prod cluster, I'd recommend running qa and dev separately so that you can upgrade those clusters first to shake out any issues. If you are going to have multiple prod clusters, then you can upgrade them one at a time to ensure application availability and sharing the clusters between environments makes a lot more sense.
Namespaces will not bring you isolation, at the moment it's just a different subdomain in dns. It's better to have namespace per application.
I highly recommend you to have two clusters for prod (in case of updating k8s) and one-two for dev/qa.
Take a look at this blog post: Checklist: pros and cons of using multiple Kubernetes clusters, and how to distribute workloads between them.
I'd like to highlight some of the pros/cons:
Reasons to have multiple clusters
Separation of production/development/test: especially for testing a new version of Kubernetes, of a service mesh, of other cluster software
Compliance: according to some regulations some applications must run in separate clusters/separate VPNs
Better isolation for security
Cloud/on-prem: to split the load between on-premise services
Reasons to have a single cluster
Reduce setup, maintenance and administration overhead
Improve utilization
Cost reduction
Considering a not too expensive environment, with average maintenance, and yet still ensuring security isolation for production applications, I would recommend:
1 cluster for DEV/QA (separated by namespaces, maybe even isolated, using Network Policies, like in Calico)
1 cluster for PROD
Definitely concur that you want multiple clusters:
anything critical to k8s that may fail during an upgrade or because you screw up somewhere will affect the whole cluster.
for example, I had an issue with DNS which wrecked havoc in my cluster; all namespaces were affected.
Upgrades are usually not a big deal but one day you might hit a roadblock; if kubelet fails for too long your pods will get killed.
So it's best to upgrade your test/dev environments and iron things out there before upgrading in prod.