Configuring Health Monitors

0:00<v Instructor>All right, it's time</v>

0:01to cover health monitors,

0:02that's what we're talking about today.

0:04So, the big question is, what are health monitors?

0:07Well, I'm sure you could take a wild guess

0:10and probably get it right

0:12because we're wanting to monitor the health of something.

0:15So, on our BIG-IP,

0:19well, we set up a virtual server that runs on there,

0:23and then what do we do?

0:24We assign a pool to that virtual server

0:27and that pool distributes connections

0:31over to our members of that pool.

0:35So, we've got all these members over here,

0:38and I have a question for you,

0:39how does the BIG-IP know

0:42whether or not that these members over here are up or down?

0:47Because if they're all down,

0:49when it forwards those connections to them,

0:51our users are gonna get some type of error,

0:54and that's something that we want to avoid.

0:57So, we need a way for the BIG-IP to know

1:00if these members over here are up or down,

1:04and that's where health monitors come into play,

1:07as you can imagine.

1:09And there's lots of different types of health monitors,

1:11and we're gonna get into that.

1:12But first of all, we're gonna start with a table.

1:15That's right, these are a table of health symbols.

1:18So, when we go into our BIG-IP

1:21and we're looking at pools

1:23and we're looking at members,

1:25we're going to see these symbols here,

1:28so we really need to understand what each of these means.

1:32We're starting off with the green circle,

1:34and green means go, it means good, right?

1:37Absolutely, a green circle means that a member

1:42or a pool is healthy and available.

1:47So, that's a good thing.

1:48Ooh, but then we get into the red,

1:49red's usually not a good thing.

1:51And here is a red diamond,

1:53and this means that a pool or member is unhealthy

1:59and, as you could imagine, unavailable.

2:03All right, that makes sense,

2:04but then I get this blue square over here,

2:06what could that be?

2:08Well, if it's a blue square, it represents unknown.

2:12And generally, this is when we first set something up

2:15and we've connected some members,

2:18but we don't have any health monitors.

2:21So, it is basically unknown

2:23if this is up or down at this point.

2:26Okay, so that's a blue square,

2:27then we come into a yellow triangle,

2:29and that generally means like a caution

2:31when we see that yellow.

2:33And that's really what this is.

2:35This is stating that a member

2:37is unavailable for some reason.

2:41And this for some reason is, I wanna state here,

2:44other than being offline.

2:48Because if it's offline, you're gonna get a red triangle.

2:52This usually means that it's unavailable

2:54because it's reached its connection limit

2:57or something along those lines.

2:59So, that is our yellow triangle

3:01kind of our caution, if you will.

3:03Then, we have a black circle,

3:06and this means that an active member

3:11has been disabled by the admin.

3:13So, an admin has disabled an active member,

3:18and this may be done so they can take it offline

3:21to do maintenance, or they're doing testing,

3:23or something along those lines.

3:25Then, we have a black triangle,

3:27and this means that an admin

3:29has disabled an inactive member.

3:34So, if a member is unactive or unavailable

3:37and we just go in there

3:38and manually as an admin disable it,

3:41well, then that's where we're gonna get that black triangle.

3:44Then, we come down to the different gray icons,

3:47and this simply indicates that this object is unavailable

3:53due to some sort of reliance on a disabled object.

3:58So, maybe this is tied to another member

4:01or something along those lines

4:03and it's unavailable because something else

4:06has been disabled which kind of impacts it,

4:08so this is kind of like a secondary impact.

4:12So, when one thing gets disabled,

4:14it kind of snowballs into a second object,

4:17and that's where we would see these gray icons.

4:20So, it's very important to remember what these are,

4:23especially when it comes to our healthy

4:25and our unhealthy and our unknown.

4:28Those are the three that you're gonna see the most often

4:31and it's very important.

4:32But we also, of course, need to be aware

4:34of these others as well

4:35because you're gonna run into them from time to time.

4:39All right, let's talk about our health monitor settings,

4:41so it says you can apply health monitors to various things.

4:46So, when it comes to these health monitors,

4:48we can apply them to four things.

4:49Number one is a node.

4:51Now, if you think back to a node,

4:54it is an IP address as the object that is a node.

4:59So, we can apply health monitors to nodes.

5:02We can also apply health monitors to pools.

5:05All right, that's pretty cool.

5:07And be aware of this,

5:10when you apply a health monitor to a pool,

5:14it's actually automatically inherited

5:16by the members of that pool.

5:20So, those members will inherit those health monitors,

5:25and we'll see that when we get into the BIG-IP.

5:28And then, we can also assign health monitors

5:30to pool members directly,

5:32and we'll see that as well when we get in there

5:34and start playing around with our health monitors.

5:36And then lastly, our links,

5:40and these are outside of the LTM,

5:42they're not within our local traffic monitor.

5:44This comes to when we're using our BIG-IP DNS

5:49and the link controller features.

5:52So, these links are connections elsewhere,

5:55and what we're doing is monitoring those connections

5:58and whether they are up or down,

6:00and that's where that health monitor comes into play.

6:02So, those are the four places

6:04that you can apply a health monitor to,

6:06our nodes, our pools, our pool members, and links.

6:11All right, super,

6:13so let's take a look at some health monitor settings here.

6:17Now, the first term we're gonna look at is interval,

6:20and this is the number of seconds between each test.

6:25And the default here is five seconds.

6:30So, when we're talking about our health monitors,

6:32we've got a monitor set up.

6:33We'll just put an M here for a monitor.

6:35Then, we've got our pool members over here, right there,

6:39and/or a pool, whatever we're monitoring.

6:41But the idea is this monitor is gonna go out

6:44and try to connect to or communicate

6:46with each of these members every five seconds by default.

6:51And it just depends

6:52on what type of health monitor you're using

6:54as to what type of communications are being done.

6:57And we're gonna dig into that,

6:58so don't get too hung up on that just yet.

7:00All right, so that's our interval,

7:02then we have timeout.

7:06And a timeout is the number of seconds

7:08before device is marked unavailable.

7:12Okay, and the default

7:14is three times the interval plus one second.

7:19So, if that's being set,

7:21our default interval is five seconds

7:26and that means that our default timeout

7:30is going to be what?

7:32Let's think about this.

7:33So, our interval is five seconds.

7:36Okay, that's our default.

7:37And our default timeout

7:39is three times the interval plus one second,

7:42so that would be 3 times 5 seconds plus 1 second,

7:47which would be, that's right, 16 seconds.

7:50That is your default timeout within the BIG-IP.

7:56Now, you can change this,

7:57you can go into these monitors

7:59and you can definitely change these values here,

8:03our interval and our timeout.

8:05And you can do that, have at it if you want to,

8:08but I'm just letting you know that these are the defaults.

8:11All right, that wraps up our intro to the health monitors.

8:14In the next nugget, we're gonna jump in

8:15and start talking about different types of health monitors.

0:00<v Instructor>Now it's time to start to analyze</v>

0:03the different types of health monitors

0:05that we have available to us.

0:07And I want you to take a look over here on the right,

0:08and this is a screenshot of our monitors list

0:12within the big IP, and this is your default monitors.

0:15And we see several here like gateway_icmp, http.

0:20There's some http with the head keyword in there, https,

0:24icmp, inband.

0:25But what do all these things mean?

0:28Well, we're gonna talk about that right now.

0:31Now, the first one we're talking about

0:33is something called an address check monitor.

0:36Now, the key word here is address.

0:40And that's because our big IP is going to go out

0:43and check the IP address

0:48of each of our member servers.

0:50And it's gonna do so in a couple different ways.

0:53Number one is using ping, okay?

0:56And that's where we're going to use an ICMP monitor

1:01or the Gateway ICMP monitor.

1:04But it's basically just going to go out

1:06and ping a member server and see if it responds.

1:09If it responds, then it is up.

1:12If it does not within that 16 seconds,

1:14then it will be marked as down.

1:16Now, there's another way you can do that,

1:18and you can do something called a TCP Echo,

1:22and a TCP Echo is still just connecting to the host

1:27to see if it's alive.

1:29It's really not checking a service or anything like that.

1:31So, really, we're just checking to see do we get a response

1:34or do we not get a response?

1:36That's what we're checking for.

1:38Now, the thing is, remember, we are checking

1:41the hosts, whether it's up or down.

1:42We are not checking the service.

1:48And what I mean by that is if we're running

1:49http for a web server, we're not checking

1:52to see if http is actually up and running and responding.

1:56We're just looking to see if the operating system

1:58of that host is up and running and networking is functional.

2:01That's all we're doing.

2:02And we're gonna see how that plays out

2:04when we get into our labs.

2:06The next one is known as a service check monitor.

2:09Now, this is different.

2:10This is where we're checking the keyword here, service.

2:14We're checking to see if that service is up or down.

2:17And we're just gonna reference an HTTP service

2:19'cause it's a web server that we're dealing with here.

2:21So, it initiates a connection to a specific service

2:25to make sure that it's running.

2:27And it could be, again, HTTP.

2:28It could be DNS or STP or SSH, lots of different services.

2:32So what it does, how this works.

2:34We know that when we're dealing with the TCP communications,

2:37there are three steps to this, right?

2:39We've got the initiator that sends a SYN

2:42to our target over here,

2:44and the target will respond with a SYN/ACK,

2:48and then the customer will respond finally with an ACK.

2:52And at that point, we have an active session,

2:54and data can flow back and forth.

2:56Well, the big IP does this a little different

2:59because we don't want to establish a session

3:02every five seconds when we're testing.

3:04That would be absolutely a waste of resources.

3:07So the way this works, the big IP, we'll go out.

3:10Let's say we're using server C here.

3:12We'll go out and send a SYN to our server

3:17to see if it's awake, okay?

3:18And that the web service on port 80, our HTTP service,

3:22is running, and that server's gonna respond with a SYN/ACK.

3:26And that's pretty normal so far

3:28when we look at TCP communications over here.

3:31But then things change.

3:33What's gonna happen is the big IP is going to respond here

3:37with a reset to reset the connection.

3:40And that way, we do not establish a session

3:47because we don't wanna do that.

3:48When you do that, it opens up and dedicates resources

3:51for communications, which would use up resources

3:54on both of our devices here.

3:55And we don't wanna do that.

3:56We simply wanna make sure we get a response here,

3:59and then we're gonna reset that connection.

4:01So, that's how a service check monitor works.

4:03It verifies that a service is running and responding.

4:07However, what it does not check is the content.

4:12So, that service could be up and running,

4:15but it could be handing out incorrect information,

4:18maybe if there was a problem with a config file

4:20or something like that along those lines.

4:22Now, when we're dealing with this,

4:23let's talk about some names of the types of monitors

4:26we're dealing with.

4:27Generally, these are going to be HTTP, HTTP2.

4:33We're gonna see HTTPS, HTTPS2 and three,

4:39and so on and so forth.

4:41So, when we're seeing these protocol names,

4:43those we should associate with a service check monitor.

4:48All right, super.

4:48So those are our service checks. Onto the next.

4:51Now, this is different. This is a content check monitor.

4:54So here, I'm gonna put content.

4:56That's our keyword, and here's what we're doing.

4:59We are going to, or well, the big IP is going to,

5:03it's gonna go ahead and it's gonna send out a SYN.

5:06All right? Super.

5:07The server's gonna send back our SYN/ACK,

5:10but then, we're not gonna send a reset.

5:14Absolutely not.

5:15What's gonna happen is we're gonna send an ACK, okay?

5:18And then we're going to send an HTTP GET command

5:23to this host by default.

5:26Now, you can change the command if you want to,

5:28but this simply says, get a copy of the webpage.

5:31It's just a web request is all it is.

5:33And then, our server's going to respond with the webpage.

5:39All right, that's great.

5:40And that means that I can then set a key word or phrase,

5:48and this webpage response is going to be analyzed

5:51to see if this key word or phrase

5:54resides in the response from the web server.

5:57So, it could be certain words that are on the webpage,

6:00and it's gonna check for those

6:01to see if they're there or not.

6:03And if they are, well, then it's good. It's up.

6:05That content is good.

6:06Otherwise, it's down. It's not good.

6:08Now, there are no default content check monitors,

6:13so I'm not gonna give you any names or anything, okay?

6:16Because you have to create all of these,

6:18and it's very simple to do.

6:20I'm gonna show you how to do it,

6:21but we're going to use the HTTP or HTTPS

6:26as a template, okay?

6:28So that we're dealing with this.

6:29And then we're gonna configure our HTTP command

6:34and our key words and, or phrases to look for

6:41within that web response.

6:44Now, the thing is, let's jump back real quick.

6:47I'm gonna jump back here to our address check monitor.

6:49And remember, this is where we're dealing with our pings

6:51and our ICMPs.

6:53This creates very little network traffic,

6:59as you can imagine.

7:00It's a simple ping, all right?

7:02So, very little network traffic.

7:04Now, as we get more complex,

7:07such as going to our service check monitor,

7:09this creates a little more network traffic,

7:15but we're not establishing a full session there,

7:18and we're not sending web data back and forth.

7:21Now, as we get to the most complicated,

7:23our content check monitor,

7:25this uses the most network traffic,

7:28or it generates the most network traffic

7:31out of all of our monitors.

7:32So, just keep that in mind.

7:34So if you're looking for something

7:35that wants to make sure a service is running,

7:38but use little bit of network traffic as possible, well,

7:42you're gonna want to use our service check monitor, okay?

7:46But if you're wanting to use the least amount

7:48of network traffic at all, and you don't care about

7:50checking to see if the service is up or not,

7:52well, then we'd go to our address checking monitor.

7:55All right, super. All right, got two more to look at.

7:58And the next one is passive monitor.

8:03Now what this does, it's passive.

8:05It doesn't actually reach out to our member servers

8:09to check to see if they're alive or not.

8:11It doesn't do that.

8:12What it does, it sends a connection to them,

8:15and this is just your standard connections

8:17from our users out here, our consumers.

8:20It goes ahead and it routes those connections to them.

8:23And what it does is it monitors the responses

8:28and the communications at Layer 4.

8:34So, here we're talking about TCP and UDP communications.

8:37It monitors those to see if everything is working properly.

8:42And if it is, then it's up.

8:45If it's not working properly, well, then it's down.

8:49And this is known as an inband monitor,

8:53and that's simply because the monitor is actually

8:56inside the big IP.

8:58It doesn't reach out to communicate with member servers.

9:01So it is inband, and that's known as a passive monitor.

9:03And as you can imagine, this creates no,

9:08big keyword there, no additional network traffic

9:12when it's doing its monitoring

9:13because it's just monitoring normal communications

9:16at Layer 4 to see if things are okay or not.

9:19And we've got our final one here, WMI,

9:21or Windows Management Instrumentation monitor.

9:25Now, the key word is Windows,

9:27because this only works on Windows servers.

9:31That's because WMI is a service that runs

9:35on a Windows server

9:36and it allows connections to be made to it

9:39and it will provide information

9:41such as performance statistics.

9:45And that's exactly what's happening here.

9:48Our host here, our big IP, is reaching out

9:51to a Windows server via WMI,

9:54and it's saying, "Hey, I'd like your statistics."

9:57It's gonna pass it back,

9:58and then the big IP is gonna analyze it,

10:01and it's gonna say, "Oh wow, you are really loaded down.

10:04I should give you less connections."

10:07It's gonna go out and check with this one,

10:08and it's going to respond "Boop, boop, boop, boop,"

10:11via, of course, WMI.

10:13And it's gonna say, "Oh, guess what?

10:15I have very little resources in use,

10:17so send me more connections."

10:20And that's how this works.

10:21Now, you do have to be running WMI on your Windows host,

10:25and it does require a little bit of configuration, okay?

10:28Now, this is a custom type of monitor,

10:33so what you do is you go down and you create a new monitor.

10:37And from the type you're gonna be selecting,

10:39you guessed it, WMI.

10:42So, those are different types of monitors

10:45that we can use within the big IP,

10:47and in the next nugget,

10:48we're gonna start configuring these things.

10:50We're gonna jump into the big IP.

10:51We're gonna get our hands dirty,

10:52and we're gonna monitor anything

10:54and everything that we can come up with, okay?

10:56Sounds like fun. See you there.

0:00<v Instructor>All right, let's get</v>

0:01to configuring some health monitors in our BIG-IP.

0:04Here we are, I've already logged into BIG-IP,

0:06and what I wanna do, I wanna go to Local Traffic,

0:09and then I wanna go to Network Map.

0:10It's gonna open up this new tab here.

0:12And what we see here is our HTTP-APP1 pool

0:16and our HTTPS-APP1 pool and we see a bunch of blue squares.

0:19Now what do the blue squares mean? Anybody?

0:23That's right, unknown because the BIG-IP doesn't know

0:27if these things are up or not.

0:29And we've got a virtual server,

0:31our pool here and our pool members,

0:33it just doesn't know if they're up or down.

0:35We need to fix that.

0:37So I'm gonna jump back over to the BIG-IP, there we go.

0:40And what we're going to do here is we are going

0:45to go down to Monitors here

0:48and we're gonna click on that, and super.

0:51And this is the default monitors that come on your BIG-IP.

0:55Now here's the thing, we do not want to edit these.

0:59That's right, we don't want to edit them.

1:01So what we wanna do is create new ones

1:04when it comes to creating monitors.

1:06Now let's take a look at one though,

1:07just so we can see some defaults.

1:08Let's pick our http.

1:10All right, we're gonna let that load up.

1:12And as we can see here, let me zoom in a little bit.

1:16We wanna come down here under the Configuration.

1:19Our default interval is five seconds,

1:21and we had talked about that.

1:22We talked about our Interval and Timeout,

1:24and our timeout was three times the interval

1:27plus one second.

1:28So then we end up with our default 16 seconds.

1:31Now we also talked about our content health monitors.

1:35So we're checking our content.

1:37And we said we sent a string, which is like an HTTP GET,

1:41and then we receive information back

1:43and we can do some comparison here with a Receive String.

1:48And that's what we're going to do a little later on.

1:51So right now I just wanted to kind of get in here

1:52to show you some of the basics in here.

1:55So now what we're gonna do,

1:56we're gonna go back to our Monitors here.

1:58All right, there they are.

1:59I'm gonna zoom out just a little bit.

2:02Now let's go over to our Pools down here.

2:07There we go, go to our Pool List

2:09and we're gonna pick on our HTTP pool.

2:11So I'm gonna go ahead and click on that, excellent.

2:14And down here at the bottom,

2:16we have Health Monitors and we played

2:18with this a little bit earlier on in a nugget

2:20where we set up one of these real quick

2:22so we could do some testing.

2:23And what we could do here is this is

2:25where we would add a monitor for this pool, all right?

2:29Now remember also,

2:30all of our member servers will inherit the health monitor

2:34of their parent pool.

2:36Keep that in mind.

2:37So let's say we go ahead and start out

2:41by looking at our Availability here.

2:44Now our Availability is a blue square, which is Unknown.

2:47It's enabled, but it's unknown,

2:48and that just means we don't have service checking enabled

2:51or there's no service check results available just yet

2:54and we're gonna fix that.

2:56So we're gonna come in here

2:56and we are going to select our gateway_icmp.

3:01We're gonna add that and we're gonna say Update, all right?

3:05And you see, it still says Unknown,

3:06so we'll give it just a couple of seconds.

3:09I'll go ahead and refresh this.

3:12And now we have our Availability as Available,

3:15green circle, and Enabled.

3:17So the pool is available, excellent.

3:21Now I want to go ahead and click on members over here,

3:24and we see we have a green circle on all of our members.

3:27And if I click on a member,

3:29we can see down here under Health Monitors,

3:32it inherited that gateway_icmp, just like I said it would,

3:36but this is how we can come in

3:37and verify that it actually does.

3:40Now if for some reason,

3:41you wanted to use a different type of monitor

3:44for a certain member, then you can change that.

3:47So we scroll down here

3:48and we look for Health Monitors down here,

3:51and there it is right there.

3:53Now that's because it's set to Advanced.

3:55If I change this to Basic, Health Monitors disappears.

3:58So if you're going down here

3:59and you don't see Health Monitors,

4:00go up and click on Advanced, there you go.

4:03Now what I can do is look at the default,

4:05which is Inherit From Pool, but I can change that.

4:08I can do Member Specific

4:10and I can add my own type of monitor that I want to

4:13for this specific member.

4:15So just because a pool member inherits from its parent pool,

4:19doesn't mean it has to use the same health monitor

4:23as its parent pool.

4:24But I'm gonna put this back to Inherit From Pool.

4:26All right, super.

4:27I'm gonna go ahead and update just

4:28to make sure everything's kosher here.

4:30There we go, super duper.

4:31All right, so we now have an ICMP,

4:34actually a gateway_icmp monitor running

4:39on this pool and its members.

4:41So now I wanna take a look at something.

4:42We're gonna run a test here

4:44and here's what we are going to do.

4:47I'm gonna run over to my Windows here, there we go,

4:51and let's just make sure everything's working as it should

4:54before we make any changes.

4:56So we'll let this open up.

4:58All right, now I'm gonna open an incognito window,

5:01and go ahead and access our servers.

5:04There we go, that's Server 1.

5:06Let's try another one, and Server 2.

5:09So it looks like it's working fine, excellent.

5:11So now I'm gonna go back to my BIG-IP

5:13and I'm gonna go back to the Properties of the pool here.

5:18We see we have our gateway_icmp

5:24monitor enabled and it's working 'cause it's available here.

5:27So I'm gonna go back to my Members real quick.

5:29Now what I wanna do is run a test.

5:32Now we're using ICMP to monitor these hosts.

5:36So what I'm gonna do is disable two of them right there.

5:39Super, and that is a black circle.

5:41So it means they've been disabled

5:43and they were active members that were disabled by an admin.

5:46That's what that black circle means,

5:47but I still have a green one here, okay, my Server 1.

5:50So now I'm gonna go over to Server 1.

5:52Let's see, there it is, F5-SVR-1.

5:54I'm gonna open this up and I'm gonna run a command here.

5:57And this command is /opt/bitnami/ctlscript.sh,

6:09and I put stop right there, stop.

6:12So what I did was stop the web services

6:14from running on this host.

6:16However, it will still respond to a ping.

6:19So if I go over here now back to my F5,

6:23remember, I'm pinging this, so if I do a refresh here,

6:25I want to, let's see here, go up and refresh this.

6:32I'm still green and I'm still able to ping that host.

6:35But remember, I turned the web service off.

6:37So what does that mean is gonna happen?

6:39Well, let's go to our page. Oh, "Site cannot be reached."

6:42Let's open an incognito window, try it again.

6:47"Site cannot be reached."

6:49Now here's what I'm trying to make a point about.

6:53When you're using ICMP to monitor application hosts,

6:58it only is checking the networking.

7:01So here, the networking's up.

7:02It thinks this host is up and just ready

7:05to take all the connections you can send to it.

7:08But in reality, the web service isn't running.

7:11So this is not a good monitor

7:14for an application host, okay?

7:16We really wanna monitor the service.

7:19And so now let's go back over.

7:20Actually, I'm gonna go ahead and re-enable these two.

7:25There we go, and now if I go back to my Windows machine,

7:27this should work.

7:29I should just get Server 2 or 3, and I get Server 2.

7:33Now I wanna go over here

7:34and I'm gonna hit the up arrow key on my Server 1

7:37and I'm gonna change that stop to start.

7:41There we go, now I started the services back, all right.

7:44So now what I want to do is go back over here

7:47and we're gonna change the monitors, okay?

7:50So what I'm gonna go back is to the pool Properties,

7:53and I'm gonna take this gateway_icmp.

7:55I'm gonna put it back over there.

7:57Now what I wanna do is I wanna grab an http monitor,

8:00put it over here, and go ahead and Update.

8:04Right now, we see our status is Unknown.

8:09So what we're gonna do is give that a couple seconds

8:11and we'll go ahead and refresh this.

8:14And now we show Available Enabled.

8:16All right, super, now let's go to Members,

8:19and we're gonna do the same thing again.

8:21I'm gonna go to here and here and disable those two.

8:26All right, they're disabled,

8:27but I still have this one up and running.

8:29So let's go make sure things are still working as it should.

8:31I should only get Server 1 at this point.

8:34Let's go ahead and Enter, there we go.

8:36Server 1, close it out, grab another incognito.

8:40Go there and Server 1 again.

8:42That's 'cause Server 1's the only one running.

8:44But if I go back to my Server 1 now

8:47and I hit the up arrow key twice

8:49so that I'm stopping that service, hit stop in 16 seconds.

8:54Over here on the BIG-IP,

8:56and actually I can come over here now to my network monitor

9:00and I can refresh the network monitor.

9:02And these are my two disabled servers over here.

9:05So let me zoom in so it's a little easier to see.

9:10There we go, so I have my two disabled,

9:13but I still have a green one over here.

9:14That's 'cause I have to wait about 16 seconds

9:16for that to go off.

9:17Let me hit this again.

9:19Now we see that this has gone to a red diamond,

9:23which means it's unavailable and offline.

9:26And my virtual server and my app pool have gone gray,

9:30which means that they're unavailable

9:32because of something they're relying on,

9:34which (laughs) are the pool members.

9:37And if I go over to my Windows host back here

9:40and I open an incognito window,

9:41what do you think is gonna happen

9:42when I try to go to the server?

9:45That's right, I'm gonna get an error

9:46because that web service isn't running.

9:48Aha, and it's in this instance,

9:52it'll be really great if I had configured a fallback host

9:55that we had talked about previously

9:56because now I would get a message saying,

9:58"Hey, we're having technical difficulties, check back soon."

10:01So what we're gonna do to fix this,

10:03we're gonna bring our web service back up over here.

10:04I'm gonna hit the up arrow twice to go back to our start.

10:08I'm gonna hit Enter.

10:10Now that has started,

10:11if I go back to my monitor here and I wait 16 seconds,

10:15well, these are gonna come back up.

10:17Now my bottom two,

10:18Server 2 and 3 are still gonna be black

10:19because I had disabled those manually.

10:21But this diamond's gonna go away

10:22and it's gonna turn into a green circle

10:24along with the green circles

10:25up at my virtual server and my pool.

10:27So let's go ahead and refresh that and see it happen.

10:31And there it goes, absolutely.

10:32Now if I go back to my Windows host, there we go,

10:35and I go ahead and hit this again,

10:37I should get my Server 1.

10:38And there it goes, absolutely.

10:40So that is why, I'm gonna go back here one more time.

10:43I'm go ahead and re-enable these.

10:45So don't forget about 'em, there we go.

10:47That's why it's very important to remember the difference

10:50between an ICMP monitor and a service monitor.

10:53ICMP is network only, service focuses on your service.

10:57If you're running web app servers

11:00or some type of service server, then yeah,

11:02you need to be using a service

11:04if there's one available in here that matches it

11:06so that you can make sure your service is up and running.

11:10All right, that wraps up our first setup

11:13on some health monitors dealing with ICMP

11:16and service-specific monitors.

11:18Now in the next nugget,

11:20we're going to set up a content health monitor,

11:24and that's really cool, so I'll see you there shortly.

0:00<v Instructor>All right, here we are on our BIG-IP,</v>

0:02and now we're gonna set up a content health monitor.

0:06So this is where we're gonna check the specific content

0:08that's being served up to us by a server

0:10to make sure it matches a keyword or string.

0:13So let's start by going into our pools, there we go.

0:16We're gonna look at our HTTP pool,

0:18that's the one we've been working on.

0:20And I'm gonna go down here and remove the health monitor,

0:23I don't want any on there at this point in time.

0:25Go ahead and update that.

0:27All right, super.

0:28Now, here's what we're gonna do.

0:30We need to create a new monitor.

0:31So let's go down to our monitors, click on that, super.

0:35And we're gonna scroll over to the side because again,

0:37we're not gonna change these default monitors.

0:39I'm gonna go over here and click create.

0:41Excellent, scroll back over. And I'm gonna give it a name,

0:44I'm gonna call this APP1-Content-Monitor, excellent.

0:51The type is going to be HTTP.

0:55And there we go, super.

0:57It brought me into the big page here,

0:59and it is an HTTP Monitor, there's my name,

1:02the parent monitor is HTTP, that's fine.

1:04Now the send string, I just want a simple HTTP get,

1:07which is just gonna pull the webpage, that's perfect.

1:10In my receive string, I need to put something in here

1:14that lets me know if a server is providing me

1:18with the correct content or not.

1:21So how are we gonna do that?

1:22Well, let's go over here to our ESX host

1:25and let's take a look at one of these pages.

1:27Now, what on this page could we use

1:31to check to make sure this page loaded correctly?

1:34So we want this to be the same across all of our servers,

1:38and I'll show you why.

1:39Let's say we've used the word Server 1.

1:42Okay, so now I'm gonna go over here

1:45and I'm gonna put in here simply Server 1.

1:49All right, go down here and click finished.

1:54All right, now I have my APP1-Content-Monitor,

1:57health monitor.

1:58So now I'm gonna go to my pools, go to my pool list,

2:02select my HTTP pool right here.

2:06Excellent.

2:07Now under my health monitors, I want that APP1 right there.

2:11There we go.

2:12And update, super.

2:16Now, oh, jumped right into available and enabled,

2:19the pool is enabled.

2:20Super, let's go to members.

2:21Oh, whoa, what's going on here? Interesting.

2:24I see a green and two blue,

2:26maybe I just need to wait a minute.

2:28Let me go ahead and click around.

2:30Let's go to policies, let's go back to pools

2:33and back to our HTTP.

2:35Okay, we're green, go back to members

2:37and oh, now look what happened.

2:41I have a green here, but I have two reds.

2:43It means they're unhealthy and unavailable.

2:46And that means if I go over to my Windows host,

2:49then I should only get Server 1, Server 1, Server 1.

2:54Let's close that out.

2:55New incognito.

2:57Server 1, yep, Server 1 again, Server 1.

3:00So interesting, and if I go to my network map over here,

3:03let me refresh this.

3:06It shows that in my HTTP pool only Server 1 is available.

3:09The others aren't, but they should be, but they're not,

3:13and here's why.

3:15If I go back over here and I go to my monitors,

3:19I go to my APP1-Content-Monitor, I put Server 1 in here.

3:23Well, that only applies to my Server 1

3:26because Server 2's website says Server 2,

3:28Server 3's websites says Server 3.

3:30I need to put something in here that's the same

3:32across all of the member servers' webpages,

3:36which would be, let's try, congratulations.

3:40Alright, let's put that in there.

3:41Congratulations!

3:45Now I'm gonna scroll down, hit update.

3:48All right, super, now let's go back to our pools,

3:52go back to our pool over here, go back to our members,

3:56and they're all green.

3:58So if I go to my network map and I do a refresh,

4:02they're all green.

4:03So now if I go back to my Windows and I hit refresh,

4:07am I gonna continue to get Server 1?

4:08Nope, I just went to Server 2 and Server 2 and Server 2.

4:13You see, that is key.

4:15When we're monitoring the health of our content,

4:18we need to make sure that that content

4:20is the same across all of our member servers.

4:23So you can't rely on something

4:24that's unique on each member server,

4:26that is a very key lesson here, because if you do,

4:29it's gonna cause you some big old headaches.

4:32So now we have three healthy hosts

4:34and we have a nice healthy pool,

4:36and we're checking for valid content.

4:39That's exactly what we want to do.

4:42So that wraps up this nugget,

4:44and in the next we're gonna talk about the difference

4:46when we're setting up health monitors

4:48between members versus nodes.

0:00<v Instructor>All right, now it's time to talk</v>

0:01about the difference between nodes and members

0:06when it comes to health monitors.

0:08So I'll tell you what, let's start with our Pool,

0:09let's go to a Pool List.

0:11We'll select our HTTP Pool because it's nice and happy.

0:15Go to Members, excellent,

0:17all of our members here are happy.

0:20Now, quick reminder, remember a member is an IP address

0:23followed by a port number like 80 right here.

0:26For HTTP, that is a member.

0:28A node is only the IP address.

0:32They are two different objects within the BIG-IP.

0:36So let's click on one of these members already

0:37'cause this is nice and green and happy.

0:39So let's click in there.

0:40Super, we got that loaded up,

0:43and down here, Availability is Available.

0:45Enabled health monitors,

0:47we're using our APP1-Content-Monitor, all is good.

0:49However, do you see a blue square in there?

0:51Because I sure do.

0:52That's because this is the Parent Node.

0:55This is the IP address of our member

0:58and it is showing blue square.

1:00But, but wait, I had set up a health monitor.

1:03Why is it not monitoring my node?

1:06Well that's because we set up a health monitor earlier

1:08for members.

1:10We need to do the same thing for our nodes

1:12if we want to monitor our nodes.

1:14So we're gonna do that by coming down here to Nodes.

1:17click on our Node List, have our three nodes,

1:19and of course, they're all blue squares.

1:22Now there's a couple different ways we can go

1:23about doing this.

1:24Number one, we can come up to the top.

1:26We got Default Monitor up here.

1:27Let's go ahead and click on that, there we go, super.

1:31And I can come in here

1:33and select a basic monitor and I'm gonna do that.

1:35I'm gonna say icmp just 'cause I want a simple ping

1:38because I'm monitoring a node, which is an IP address.

1:42I just wanna know if that IP is up or not.

1:44I'm not monitoring a service

1:45because a service is part of a member.

1:48All right, super, so I'm gonna say Update.

1:51Hey, there we go, all right, super.

1:53Let's go back to our Node List now.

1:55And you'll see our nodes are no longer a blue square,

1:57but a green circle, meaning they are up in fantabulous.

2:01All right, but that's not the only way we can do this.

2:03We can do this another way.

2:05We can click on an individual node here

2:06and let's just go into the server one here.

2:09All right, super.

2:11And here we see our availability is green, we're good to go.

2:14Our health monitor is icmp here.

2:17And if we scroll to the bottom, we see Health Monitors,

2:21and this is set to Node Default.

2:23So it's gonna be whatever the default setting is

2:26that we just set for the nodes.

2:28But I can go in here and say Node Specific if I want

2:31and check one of these others,

2:33I can use something like SNMP or gateway_icmp.

2:37I can do those if I want or I can say None.

2:41Now if I say None and do an Update,

2:42what do you think's gonna happen?

2:44That's right, we're gonna get that blue square

2:46just like that again and we want to avoid that.

2:49So let's go ahead and we'll just leave it at Node Default

2:52for now and go ahead and Update.

2:54And it's checking the Health Monitor, that's pretty cool,

2:56a little clock.

2:58There it goes and we'll let it refresh here

3:02and we'll click off of there, we'll go to Pools,

3:04and then back to Nodes and there we go.

3:08Our node is healthy again with icmp.

3:11So again, if we go back to Nodes,

3:13let's go back to our Nodes List there.

3:15You can set your Default Monitor up here at the top,

3:17or you can go into individual nodes

3:19and set them there if you would like.

3:21But either way we should think

3:23about setting up health monitors at the node level,

3:26so we can monitor those as well.

3:29All right, super, that wraps up our health

3:32of members versus nodes.

0:00<v ->Alright, for the skill validation, you have been asked</v>

0:02to set up a custom health monitor for our

0:05HTTPS pool.

0:08Alright, super.

0:09So what we're supposed to do is go in

0:11and create a custom health monitor named app one dash

0:14HTTPS, using the HTTPS type of monitor.

0:18Alright, super.

0:19And use something other than the word congratulations.

0:22So let's go ahead and do this.

0:23So let's go ahead and take a look at our HTTPS.

0:25We can see here that it is a blue square, so we know

0:29that it's unknown at this point.

0:31So we need to create a custom monitor.

0:32And the way we do that, is come down to our monitors,

0:35click on that, and we scroll to the right

0:38and we select create.

0:40And it said here, we're supposed to use the name.

0:43Let's put this in here, H, app one dash HTTPS.

0:48All right, super, and the type is supposed to be HTTPS.

0:53All right, that's easy enough, there we go.

0:55And the receive string is what we have to change

0:58to do a content check.

1:00So we need to put something in here

1:01that resides on all of our webpages.

1:03So let's go back over to our Windows host

1:05and I don't need that.

1:07So let's close this out there.

1:09Alright, so what on here could I use to check to make sure

1:14that this webpage loaded correctly?

1:16Well, I could basically just copy this, how about that?

1:19Let's just do that, but I'm not gonna be able

1:22to copy and paste it over there.

1:23So let's do this.

1:24It says you are now running NGINX open source

1:26packaged by Bitnami.

1:28So let's, let's use this, NGINX,

1:30open source packaged by Bitnami.

1:33NGINX open source.

1:35Alright, so we're gonna go in here, NGINX.

1:38Oh, I should check to see if it's capitalized

1:40because that may, open source packaged by Bitnami.

1:43Okay, open source, packaged by Bitnami.

1:49There we go, that should work.

1:51All right, so now let's go ahead and scroll to the bottom

1:54and say finished.

1:57Now I have my app one HTTPS health monitor, super.

2:01So let's go now to our pools.

2:04Go to our pool list,

2:05'cause I wanted to apply this to my HTTPS pool.

2:08We're gonna go here, under our health monitors,

2:11we're gonna select our app one HTTPS, slide it on over

2:13and click update.

2:15All right, super.

2:17Now we need to go ahead

2:19and click on our members up here and lookie there.

2:22They're all green, so that is good.

2:25Lemme go back to properties and make sure

2:26it has come up as well.

2:27Yep, our pool available enabled this pool is enabled, super.

2:31Members, now let's go to make sure it works.

2:34And here I'm going to change this to HTTPS.

2:38So here, https colon slash slash enter and there it goes,

2:44server two.

2:45And try it again, still server two.

2:49Let me open up a new incognito window just to make sure.

2:53Here we go, new incognito.

2:56And I'm gonna go HTTPS, colon 172 dot 16 dot 101 dot 11.

3:00And there we go.

3:02Not private, yeah, there we go.

3:03Advanced, proceed, there it goes, and server two.

3:07So yes, it is absolutely working.

3:10Alright, congratulations on setting up your custom

3:13HTTPS content monitor.

3:16I hope this has been informative for you

3:18and I'd like to thank you for viewing.