PRIYANKA VERGADIA: Welcome to get Cooking in Cloud,
where we share the best recipes to apply in your cloud kitchen.
I'm Priyanka, and in this episode,
we'll share the recipe to plan a warm DR
pattern for your application that are deployed on premise.
So let's dive in.
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A little recap.
In the last episode, we were talking about Main Street art
that runs through applications on premise
and our building a DR infrastructure on Google Cloud.
And we helped them set up a cold DR plan.
Well, Main Street art has changed a bit since then.
They now need to setup a warm stand by DR pattern
to keep the RTO and RPO values as small as
possible without the effort and expense of a fully
HA configuration, which means to support a disaster,
they need some replication and redundancy
built into the system.
Well, let's see how this would work.
We create a VPC network, then we configure the connectivity
between the on-premise network and the Google Cloud network.
We replicate the on-premise servers to the Compute Engine
instances, then create snapshots of the web and application
server instances.
We then create a custom image of the database server
on Google Cloud with the same configuration as on premise.
Then we start a database instance in Google Cloud using
that custom image and attach a persistent disk
to the instance for database and transaction logs,
configure the replication of the database server,
set auto delete flag on the persistent disk
to no auto delete.
We do this so that our persistent disk will not
be inadvertently deleted since that would be a disaster,
configure a scheduled task to create
regular snapshots of the persistent disk of the database
instance on Google Cloud, then test the process of creating
instances from the snapshots by creating the web
and application server, also create a script that copies
updates to the web application and the application server
whenever the corresponding on-premise servers are updated,
write the script to create a snapshot of the updated
service, then configure Cloud DNS to point
to the internet-facing web service on premise.
Then a disaster hits.
All Main Street art needs to do is to resize the database
server instance to handle the production load,
use the web and application server snapshots to create
new web and application server instances
and then test that it all works.
Once tested, point the Cloud DNS to their web service
on Google Cloud.
When the production environment is running on premise again
and can support production workloads,
Main Street art has to reverse the steps that they
followed during the failover.
A typical sequence to return to the production environment
is we take a backup of the database running on Google
Cloud, then copy and apply the backup files to the database
in the production environment.
Then we prevent connections to the application
in Google Cloud.
One way to do this is to prevent connections to the web server
by modifying the firewall rules.
From this point, the application will be unavailable
until we finish restoring the production environment.
Don't forget to copy any transaction log files over
to the production environment and apply
to the database in that environment.
Test that the application works as expected
by simulating the user scenarios on the production environment.
Configure Cloud DNS to point to the on-premise web service,
then delete the web server and the application
server instances that are running in Google Cloud,
resends the database server on Google Cloud back
to the minimum instance size that
can accept replicated data from the on-premise production
database, then configure replication
between on-premise database server
and the database server in Google Cloud
by following the instructions for your specific database
software.
Well, there you have it.
If you are running your application on premise and need
to keep the RTO and RPO values as small as possible
without the expense of a fully HA configuration,
then a warm DR pattern is the way to go.
We learned how to approach recovering
the environment from failure in a warm DR scenario.
That's all for today on Get Cooking in Cloud.
I'm hoping you're cooking up your own DR strategy.
Join us next time where we will share the recipe
to implement a hot DR pattern.
If you like this video and would like to see more such content,
don't forget to like and subscribe to our channel.
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