What do you need to know about cluster networking for exam AZ‑801?
Well, for this part of the exam, if you're asked about it at all,
it's just what are some inbox Windows Server features that
can make your network run more efficiently?
Because, as I mentioned in the previous module,
high availability is about redundancy, isn't it?
So, ideally, your cluster nodes have redundant hardware network interface cards,
or NICs.
If those NICs are fairly current, they should support RDMA,
or Remote Direct Memory Access.
That would allow those NICs to access remote storage almost as
fast as the server can get to its own storage,
you see?
Now,
we can combine RDMA compatible network interfaces with
the Server Message Plock protocol.
The SMB 3 protocol and SMB Direct allow you to take
advantage of that RDMA capability of your NICs.
And again, in the name of file share in particular,
accessing file data on shares using the SMB protocol,
can be very fast and efficient in terms of internode communications.
Lastly, in Windows Server we have NIC teaming,
which is where you can create a logical network interface that
actually maps to two or more physical interfaces.
This allows you to do bandwidth bonding,
which gives you increased throughput,
but also gives you high availability at the network interface level because
if you lose a NIC due to a planned or unplanned outage,
as long as you have at least one other network
interface in the team that's available,
then that server can continue to communicate,
all right?
So we could go beyond this, we really don't have to though,
but we want to think about things like multi‑path
I/O and redundant connectivities.
You might have multiple network paths.
You might want to separate, for example,
your storage, network traffic, your cluster internal traffic,
that is your heartbeat traffic, and then your data traffic.
If you can do that,
if you have the network infrastructure and the
hardware to support that topology,
all of those things are good because they increase
the resiliency of your cluster, they increase the performance of your cluster,
and give you as much high availability as you can get.
Cluster Workload Options.
All of this setup is well and good, but ultimately it comes down to well,
great, now that we have the failover cluster up and running and it's functional,
what exactly can we do as far as making applications
and services highly available?
What is supported?
Well, no surprise,
many of the most common Windows Server roles are supported
out of box for Windows Server clustering.
The distributed file system, or DFS,
you can make a DFS namespace highly available.
This, again,
it brings up the idea of redundancy because if you know much about DFS,
we cover DFS in great depth by the way in AZ‑800,
DFS allows you to aggregate file shares from across your environment and
create a single logical tree view of those shares,
and you can replicate those shares, you can replicate your namespace,
so it's nice that as an option you can put your namespace in a failover
cluster to give yet more high availability to it.
File server is another built‑in clustered role.
This would be an active‑passive file share, and then there's the
Scale‑Out File Server, or SOFS, option as well for virtual machines and
for SQL Server databases. You can take Hyper‑V VMs themselves and make
them highly available as clustered roles.
You're using Hyper‑V Replica to replicate virtual machines and
you want to replicate VMs that are in a cluster, then you'll
want to have the Replica Broker.
In fact you'll need to have an instance of the Replica Broker as
a clustered role. Dynamic Host Configuration Protocol can be
critical for a business whose endpoints received their TCP/IP
configurations dynamically.
Again,
this is one way. I mean Microsoft's DHCP server does have its own
failover capability, so I don't want to lead you down the path to
think that there's only one solution to the problem of high
availability. There really never is.
Now you'll see that in Windows Server failover clustering there's a
generic catch‑all for generic app, script, or service.
So this is to remind us that we're not limited only to the clustered roles
that Microsoft gives us that it hosts as you see on the slide. You can always
make your own application service or script highly available by using the generic template in Failover Cluster Manager.