Say you have 3 or more services that communicate with each other constantly, if they are deployed remotely to the same cluster all is good cause they can see each other.
However, I was wondering how could I deploy one of those locally, using minikube for instance, in a way that they are still able to talk to each other.
I am aware that I can port-forward the other two so that the one I have locally deployed can send calls to the others but I am not sure how I could make it work for the other two also be able to send calls to the local one.
TL;DR Yes, it is possible but not recommended, it is difficult and comes with a security risk.
Charlie wrote very well in the comment and is absolutely right:
Your local service will not be discoverable by a remote service unless you have a direct IP. One other way is to establish RTC or Web socket connection between your local and remote services using an external server.
As you can see, it is possible, but also not recommended. Generally, both containerization and the use of kubernetes tend to isolate environments. If you want your services to communicate with each other anyway being in completely different clusters on different machines, you need to configure the appropriate network connections over the public internet. It also may come with a security risk.
If you want to set up the environment locally, it will be a much better idea to run these 3 services as an independent whole. Also take into account that the Minikube is mainly designed for learning and testing certain solutions and is not entirely suitable for production solutions.
I have spent the last 6 hours reading through buzzword-riddled, lofty, high-level documents/blogs/articles/slideshares, trying to wrap my head around what OpenStack is, exactly. I understand that:
OpenStack is a free and open-source cloud computing software platform. Users primarily deploy it as an infrastructure as a service (IaaS) solution.
But again, that's a very lofty, high-level, gloss-over-the-details summary that doesn't really have meaning to me as an engineer.
I think I get the basic concept, but would like to bounce my understanding off of SO, and additionally I am having a tough time seeing the "forest through the trees" on the subject of OpenStack's componentry.
My understanding is that OpenStack:
Installs as an executable application on 1+ virtual machines (guest VMs); and
Somehow, all instances of your OpenStack cluster know about each other (that is, all instances running on all VMs you just installed them on) and form a collective pool of resources; and
Each OpenStack instance (again, running inside its own VM) houses the dashboard app ("Horizon") as well as 10 or so other components/modules (Nova, Cinder, Glance, etc.); and
Nova, is the OpenStack component/module that CRUDs VMs/nodes for your tenants, is somehow capable of turning the guest VM that it is running inside of into its own hypervisor, and spin up 1+ VMs inside of it (hence you have a VM inside of a VM) for any particular tenant
So please, if anything I have stated about OpenStack so far is incorrect, please begin by correcting me!
Assuming I am more or less correct, my understanding of the various OpenStack components is that they are really just APIs and require the open source community to provide concrete implementations:
Nova (VM manager)
Keystone (auth provider)
Neutron (networking manager)
Cinder (block storage manager)
etc...
Above, I believe all components are APIs. But these APIs have to have implementations that make sense for the OpenStack deployer/maintainer. So I would imagine that there are, say, multiple Neutron API providers, multipe Nova API providers, etc. However, after reviewing all of the official documentation this morning, I can find no such providers for these APIs. This leaves a sick feeling in my stomach like I am fundamentally mis-understanding OpenStack's componentry. Can someone help connect the dots for me?
Not quite.
Installs as an executable application on 1+ virtual machines (guest VMs); and
OpenStack isn't a single executable, there are many different modules, some required and some optional. You can install OpenStack on a VM (see DevStack, a distro that is friendly to VMs) but that is not the intended usage for production, you would only do that for testing or evaluation purposes.
When you are doing it for real, you install OpenStack on a cluster of physical machines. The OpenStack Install Guide recommends the following minimal structure for your cloud:
A controller node, running the core services
A network node, running the networking service
One or more compute nodes, where instances are created
Zero or more object and/or block storage nodes
But note that this is a minimal structure. For a more robust install you would have more than one controller and network nodes.
Somehow, all instances of your OpenStack cluster know about each other (that is, all instances running on all VMs you just installed them on) and form a collective pool of resources;
The OpenStack nodes (be them VMs or physical machines, it does not make a difference at this point) talk among themselves. Through configuration they all know how to reach the others.
Each OpenStack instance (again, running inside its own VM) houses the dashboard app ("Horizon") as well as 10 or so other components/modules (Nova, Cinder, Glance, etc.); and
No. In OpenStack jargon, the term "instance" is associated with the virtual machines that are created in the compute nodes. Here you meant "controller node", which does include the core services and the dashboard. And once again, these do not necessarily run on VMs.
Nova, is the OpenStack component/module that CRUDs VMs/nodes for your tenants, is somehow capable of turning the guest VM that it is running inside of into its own hypervisor, and spin up 1+ VMs inside of it (hence you have a VM inside of a VM) for any particular tenant
I think this is easier to understand if you forget about the "guest VM". In a production environment OpenStack would be installed on physical machines. The compute nodes are beefy machines that can host many VMs. The nova-compute service runs on these nodes and interfaces to a hypervisor, such as KVM, to allocate virtual machines, which OpenStack calls "instances".
If your compute nodes are hosted on VMs instead of on physical machines things work pretty much in the same way. In this setup typically the hypervisor is QEMU, which can be installed in a VM, and then can create VMs inside the VM just fine, though there is a big performance hit when compared to running the compute nodes on physical hardware.
Assuming I am more or less correct, my understanding of the various OpenStack components is that they are really just APIs
No. These services expose themselves as APIs, but that is not all they are. The APIs are also implemented.
and require the open source community to provide concrete implementations
Most services need to interface with an external service. Nova needs to talk to a hypervisor, neutron to interfaces, bridges, gateways, etc., cinder and swift to storage providers, and so on. This is really a small part of what an OpenStack service does, there is a lot more built on top that is independent of the low level external service. The OpenStack services include the support for the most common external services, and of course anybody who is interested can implement more of these.
Above, I believe all components are APIs. But these APIs have to have implementations that make sense for the OpenStack deployer/maintainer. So I would imagine that there are, say, multiple Neutron API providers, multipe Nova API providers, etc.
No. There is one Nova API implementation, and one Neutron API implementation. Based on configuration you tell each of these services how to interface with lower level services such as the hypervisor the networking stack, etc. And as I said above, support for a range of these is already implemented, so if you are using with ordinary x86 hardware for your nodes, then you should be fine.
Having received no replies on the Couchbase forum after nearly 2 months, I'm bringing this question to a broader audience.
I'm configuring CB Server 2.2.0 XDCR between two different Openstack (Essex, eek) installations. I've done some reading on using a DNS FQDN trick in the couchbase-server file to add a -name ns_1#(hostname) value in the start() function. I've tried that with absolutely zero success. There's already a flag in the start() function that says -name 'babysitter_of_ns_1#127.0.0.1' so I don't know if I need to replace that line, comment it out, or keep it. I've tried all 3 of those; none of them seemed to have any positive effect.
The FQDNs are pointing to the Openstack floating_ip addresses (in amazon-speak, the "public" ones). Should they be pointed to the fixed_ip addresses (amazon: private/local) for the nodes? Between Openstack installations, I'm not convinced pointing to an unreachable (potentially duplicate) class-C private IP is of any use.
When I create a remote cluster reference using the floating_ip address to a node in the other cluster, of course it'll create the cluster reference just fine. But when I create a Replication using that reference, I always get one of two distinct errors: Save request failed because of timeout or Failed to grab remote bucket 'bucket' from any of known nodes.
What I think is happening is that the Openstack floating_ip isn't being recognized or translated to its fixed_ip address prior to surfing the cluster nodes for the bucket. I know the -name ns_1#(hostname) modification is supposed to fix this, but I wonder if anyone has had success configuring XDCR between Openstack installations that may be able to provide some tips or hacks.
I know this "works" in AWS. It's my belief that AWS uses some custom DNS enabling queries to return an instance's fixed_ip ("private" IP) when going between availability zones, possibly between regions. There may be other special sauce in AWS that makes this work.
This blog post on aws Couchbase XDCR replication should help! There are quite a few steps so I won't paste them all here.
http://blog.couchbase.com/cross-data-center-replication-step-step-guide-amazon-aws
I've got a group of servers that currently use both memcached and repcached side by side (listening on different ports). The memcached service is used to store local data that doesn't need to be shared. The repcached instance is used to allow pairs of servers to collaborate.
When I found Couchbase I was really excited because it looks like it would allow me to:
Make some data persistent
Share with more than two nodes
Leave most of my code as-is since it uses the memcached API
So I installed Couchbase but I've run into a problem--it doesn't look like there's a way to setup two clusters on the same server. I'd like one cluster that doesn't share with any other server and a second cluster that does share with other servers.
Yes, I could setup several dedicated servers for Couchbase to create different clusters but I've got plenty of CPU + ram to spare on the servers that are currently running memcached + repcached so I'd prefer to just replace those services with Couchbase.
Is it possible to run two instances of Couchbase on the same host? I realize I'd have to change some ports around. I just haven't seen anyone talking about doing anything like this so I'm thinking the answer is "no"... but I had to ask because it looks like Couchbase would be perfect for my needs.
If this won't work then I'd be interested in any alternative suggestions. For example, one idea I had was using Memcached + MemcacheDB to emulate a persistent non-shared Couchbase cluster. However, I don't like the fact that MemcacheDB doesn't support expiring records and I'd rather not have to write a routine to delete millions of records each month (and then wonder if performance will degrade over time).
Any thoughts would be appreciated. :-)
The best solution here is probably to run a single instance of Couchbase and create one memcached bucket and one Couchbase bucket. The memcached bucket won't have persistence and will function exactly like memcached. The other bucket will have persistence and supports the memcached api. You can create as many buckets as you want in a single Couchbase server.
Your other option is to virtualize and run a Couchbase server on each vm.
I am setting up private cloud for some experiments using xen as the hosting system. But I am faced with a problem for which I can't seem to get solutions.
I have to do some kind of automatic provisioning of VMs given the server load. Eg: if server of type A gets to lets say 60% load the cloud should spawn off another vm instance of the same type to distribute the load(using the netscalar).
Is there an opensource system that can help me or how do I go about developing scripts to do the same.
If I understand you correctly, you want to live-migrate the VMs depending on the load of the host. You can use OpenNebula to help you with this. You can use the advanced scheduler named Haizea with OpenNebula.
While I've never tried this, but you can use this with ONE's APIs to create more VMs if a VM gets too much load.
Take a look at http://openstack.org/
It's opensourced.
OpenStack and OpenNebula are already mentioned, there are two more IaaS open-source projects:
Eucalyptus
Nimbus
use apache cloudstack, it is open-source and it has tight integration with netscalar Load Balancers and F5 Load balancers, check below link for Netscalar LB creation and VM creation. Rules can be set on these and new VMs ca be spanned based on Load.
https://cloudstack.apache.org/docs/api/apidocs-4.5/TOC_Root_Admin.html
There is a Cloud platform called Nimbo that lets you do this and more out of the box... http://www.hcltech.com/cloud-computing/Nimbo/ .