(iNE jingle)
- In this video, I'd like to talk about
a very useful tool within GNS3.
It's an optional tool, but it, like I said,
can be very useful to you, called the Snapshot tool.
So first of all, let me paint you a picture.
Let's start with a basic GNS3 topology,
such as this one.
I'll zoom in on this here.
So, let's say my objective here is to practice EIGRP,
maybe by itself, then practice OSPF by itself,
and then maybe practice the redistribution of EIGRP
into OSPF and just basically use
this simple topology here and make
multiple permutations to it, change it multiple times.
And here's what I'm thinking.
I'm thinking that maybe once I start out,
maybe I just want to start with a simple topology
of just IP addresses and that's it.
And then later on, add on EIGRP to that,
but at some point in time, I might want to go back
to that initial topology where everything was connected
and all it had was IP addresses.
Go back to the time before it had
any routing protocols configured.
And also, maybe after I initially create EIGRP
and I have that running, maybe in the future
I want to go back to that.
Maybe in the future, after I've got OSPF and EIGRP
redistribution working just fine, I say to myself,
okay, I'd like to go back to them time
when I didn't have OSPF.
When I had all my IP addresses, when I had EIGRP working,
but before I had all my OSPF.
In other words, I want to have the ability
to go back and forth in time between different topologies
to be able to play around with adding things,
changing things, and that is what Snapshots are used for.
Where, within a project, you want to be able
to go back and forth in time between
what that project looked like at various states in time.
Now, one of the things you might be wondering,
because this was a question that came up with me was,
well, why don't I just create multiple projects.
In other words, why don't I have one project
that is simply this topology
with nothing but the IP addresses in it,
and then why don't I create another project that has
this topology with the IP addresses and EIGRP in it,
and then maybe a third project that has this, EIGRP
and OSPF running, and then if I wanna just
go back and forth, I'll just open up
different project files to do that.
Why would I use the Snapshot tool
instead of just using multiple projects?
Well, here's the reason why.
Basically, at a high level, it comes down to
memory consumption, that's what it boils down to.
For example, look here in my folder
where my projects are located.
My users, my name, GNS3 and projects.
And you can see, right now
I've just got four projects in here.
Well, if I click on one, just select it,
and then I right click and hit properties,
notice that one project,
524 megabytes of memory for that.
Okay, what about the next project?
Right click, properties,
once again 532 megabytes of memory.
So this is the downside of using,
or I should say creating multiple projects
if all you wanted to do was go back and forward
with the same topology,
but adding different stuff to that topology,
or changing the topology.
It's gonna eat up tons of memory in your laptop or PC
if the way you're doing that
is by creating multiple projects.
This is where the Snapshot tool is really beneficial,
'cause everything within the snapshot
stays within this one project.
As an example, just let me go ahead
and close this right here.
So in this particular topology, I have so far
created two snapshots.
The first snapshot was just IP addressing,
and that was it.
All the links are up, IP addressing was configured,
nothing else was configured.
So, let's go back to that one.
So, and then I'll show you how to actually
create new snapshots.
So, the first thing I'm gonna show you is,
if you've already got a snapshot running,
how do you go back to it?
In other words, if you've created a snapshot in the past,
how do you revert back to that snapshot?
So let's say that right now, this topology
actually was running EIGRP, it actually was running OSPF,
there's all sorts of authentication
and other fun stuff in here, I say, okay,
I'm done with that.
Now I wanna go back to my real primitive topology
that all it had on it was IP addressing that's it.
So, step number one, and this is the critical thing,
when using the Snapshot tool to either
create a new snapshot or to restore back
to what a previous snapshot looked like,
main thing to remember, all of your devices,
all of your routers and ethernet switches
have to be turned off.
So anything that's running Cisco IOS,
don't worry about the built-in nodes
like Cloud and Host and all that stuff,
but anything that's running IOS,
your etherswitch modules and your routers,
has to be in the off state.
If you try to create a new project
while routers are currently running,
or if you try to revert back to an old project
while stuff is currently running,
you're gonna have unpredictable results.
A lot of times, what I've seen is that
it just doesn't work.
It takes you right back to the same place where you were
before you went into Snapshots.
So make sure that all of your IOS devices are turned off
before using Snapshot in any way, shape or form.
So, now I want to revert back to an old snapshot,
so, number one, stop all my devices.
Now that they're all stopped,
go up to this tool right here.
This is the, as you can see, Manage Snapshots tool.
And you're gonna wanna click on that.
And you can see, in this particular project,
I've already created two snapshots,
so I'm gonna click on the one, and you can see,
when you create a snapshot you,
you're gonna wanna give it some sort of descriptive name
so you can remember what your topology was like,
what it was doing at that point in time.
So I'm gonna click on IP addressing only
and I'm gonna click on restore.
And it warns you, it says okay, if you do this,
anything that's currently in your running config
that hasn't been saved is gonna be gone,
it's gonna be wiped out.
I say yeah, okay, well that's actually what I wanna do,
I wanna wipe out the current state
and revert back to the previous state.
Okay, so here I am, now actually, if my,
probably what I should have done
is when I first started this,
I probably shouldn't have labeled in like EIGRP and OSPF,
I probably, when I created the snapshot,
it probably would have made more sense
just to have the actual picture look like the routers,
the links, and the IP addresses,
'cause right now, looking at this,
I know it kinda looks confusing, like,
well, wait a second, is he still running EIGRP and OSPF?
No, I'm not, and here's how I can show you.
I'll go ahead and start everything up.
Alright, now it's running.
Now, I'm just gonna get into one of my devices.
Let's say R2.
And the way I know that the snapshot
worked the way that I reverted back,
is that when this device comes up,
if I do show ip interface brief,
actually, let me go ahead and just make the font size
a little bit larger for you guys,
so you can read it a little bit easier on the video.
There we go.
show ip interface brief.
So you can see, right now, my IP addresses are there,
it remembered that at the time I took this snapshot
those interfaces were actually up up and connected,
and if I do show ip protocols, you can see there's nothing.
So right now, this is before I configured
any routing protocol at all.
All I had were IP addresses.
Now let's go ahead and close this window.
And now I say, okay, well what I'd like to do now
is move forward in time.
I wanna go forward in time to when I created the snapshot
when my EIGRP was up and functional.
Okay, click stop.
Stop everything.
Go to the Snapshot button again.
Select the snapshot that you previously created,
and restore.
Once again, you get the warning.
Alright, everything should be back,
so now let's start everything up again.
So, how do I know that worked?
How do I know that it restored me
back to that point in time when,
not only the IP addresses were here,
but I had also configured EIGRP.
Well, once again, let's just
double-click on a router, R2 here.
Show ip interface brief,
verify that my IP addresses are still there, yep.
And now show ip protocols,
and you can see, I've got EIGRP running.
Show ip eigrp neighbor,
I have an EIGRP neighbor.
So it now brought me to that point in time.
So now let's take it one step further.
Let me show you how to create a brand new snapshot.
So in order to do this,
I'm gonna take up, with my existing topology,
and now I'm gonna configure just a basic OSPF adjacency
between R2 and R3.
So let's bring up R3 here.
Alright, so let's start with R2,
router ospf 1
network, and in this particular case,
it's gonna be the 2.3.2 network.
And that's gonna be in area zero.
And that's all I'm gonna do,
I'm not gonna do any redistribution right now,
I'm just gonna get my EIGRP up and working.
Now, notice once thing I did,
which is just very, very important.
I'll zoom in on this.
In this particular case,
I issued the write memory command.
It's kind of abbreviated here, but I could also have issued
the copy run start command.
Why is that important?
Because when you take the snapshot, when you create it,
at that moment in time, it takes a snapshot
of the current saved configuration,
the startup configuration of your devices.
It does not take a snapshot of your running configuration.
So if you have a running configuration
with any unsaved changes,
they will not be a part of your snapshot.
So make sure you save all your configs
with copy run start or write memory, whichever you prefer,
then make sure you shut down all your routers,
power them off, and then take the snapshot.
Alright, so.
So I saved my configuration here,
so now let's go into, I'm done with Router 2,
let's go into the other router.
And actually, before I do this,
I will just copy that part of my OSPF configuration
so I can just copy and paste it.
Make life easy for myself.
Alright, now let's get into the other router.
Paste all that stuff in.
Ah, it didn't work, okay, so
let's go back over here.
There we go.
So we should see now, OSPF takes a little bit longer than
EIGRP to do its stuff, but, there we go.
Now the OSPF adjacency is up.
Show ip ospf neighbor
Great, now I have to remember
to save the configuration in this guy.
Alright, so now I've saved the configuration
in both routers,
I will shut this terminal application down.
I will turn off my routers.
And now, once again, I'll go to the Snapshot tool,
and this time I'll select Create.
And I'll give it a name.
OSPF-EIGRP-
No-Redistribute
That's just my name.
It saves it, and I close it.
Now, where does it actually save these snapshots,
you might be wondering, are these snapshots gonna be good
even after I close this project and completely walk away,
what if I close my laptop?
Are the snapshots still in there?
Yes, they are, and here's how we can see.
So everything's closed, let's go ahead and quit from GNS3,
and now I'll go into my file where all of my GNS3 stuff is.
Here's Projects.
So, I'll select that Snapshot Test,
that's the one I was doing, and under Project Files,
you can see right there, it has a category called snapshots.
And if I double-click on that,
there are all the snapshots that I created.
So now let's go ahead and,
and notice, if I go back to the Project file,
that's all contained within that one project,
so that one project now, that has multiple snapshots in time
it exceeded the size a little bit,
you know, the other projects were like
500 and something megs, now in this particular case,
we're up to 799 megabits, but still,
that's a lot less memory than if I had created
three or four separate projects,
rather than three or four snapshots.
So, okay.
So now let's go back to GNS3 and start it up again.
I will open that project.
Now, by default, when you open the project,
GNS3 will open it to the most recent snapshot that you took.
So right now, it should have opened it
to my EIGRP OSPF snapshot, 'cause that was the very last
one that I took before I shut everything down.
Let's confirm that.
So, I'lljust open up R2 and, if I'm right,
R2 should now be running EIGRP and OSPF.
And here's how we can tell.
Show ip eigrp neighbor
Yep, I have an EIGRP neighbor.
Show ip ospf neighbor
And there's my OSPF neighbor.
I say, okay, well, I wanna go back in time when
all I had were IP addresses.
Maybe I wanna get rid of EIGRP and OSPF
and I wanna configure RIP and BGP.
Okay, well, rather than unconfiguring everything,
I will just stop all my routers,
go to my Snapshot tool,
go to my very first snapshot,
restore,
alright, now start 'em all up again.
And now when I go into R2, we should see,
let me make this a little bit larger for you,
so now, because I went to my first snapshot,
if I do show ip protocol, I have nothing.
But if I do show ip interface brief,
I still have my IP addresses.
And that is how you use the Snapshot tool.
(iNE jingle)