1 00:00:00,000 --> 00:00:14,240 Hey guys and welcome back. 2 00:00:14,240 --> 00:00:17,760 So in this nugget right here, what I want to talk to you about is iSCSI. 3 00:00:17,760 --> 00:00:23,559 Now if you are unfamiliar or can't quite remember what a SCSI drive is, let me just show you 4 00:00:23,559 --> 00:00:24,560 what they are. 5 00:00:24,560 --> 00:00:28,000 So we can see here what a SCSI device this is what it looks like here. 6 00:00:28,000 --> 00:00:33,439 And it was as we can see here once very common for connecting small to medium sized computers 7 00:00:33,439 --> 00:00:35,759 over this particular cable. 8 00:00:35,759 --> 00:00:39,560 But like we see here there are now faster standards such as USB. 9 00:00:39,560 --> 00:00:42,159 In fact let me just quickly get a better image. 10 00:00:42,159 --> 00:00:45,640 You can kind of see these ports here this is what we're talking about. 11 00:00:45,640 --> 00:00:50,760 Now obviously this is all about having a physical connection. 12 00:00:50,760 --> 00:00:56,280 So that would mean having a computer here and one close enough whereby you could attach 13 00:00:56,280 --> 00:00:58,679 a SCSI and have that connection. 14 00:00:58,679 --> 00:01:04,879 But this was obviously very very limited and because of this something else was invented 15 00:01:04,879 --> 00:01:09,640 effectively this was iSCSI which is the purpose of what we're going to talk about in this 16 00:01:09,640 --> 00:01:10,640 nugget. 17 00:01:10,640 --> 00:01:15,879 Now what iSCSI is it is internet small computer system interface. 18 00:01:15,879 --> 00:01:20,480 So what we're really talking about is getting that SCSI connection but instead of a physical 19 00:01:20,480 --> 00:01:25,960 connection connecting a cable we're going to have this connection over the network. 20 00:01:25,959 --> 00:01:32,239 So instead of using wires and cables we will enable this connection directly using TCPIP. 21 00:01:32,239 --> 00:01:37,879 Now in order to be able to understand iSCSI we have to understand some basic concepts. 22 00:01:37,879 --> 00:01:40,759 Now the first concept is going to be a target. 23 00:01:40,759 --> 00:01:44,959 The second concept is going to be an initiator. 24 00:01:44,959 --> 00:01:51,479 Also we have the term WWID which is a world wide identifier. 25 00:01:51,479 --> 00:01:53,679 And the last term is a LUN. 26 00:01:53,720 --> 00:01:56,200 This is a logical unit number. 27 00:01:56,200 --> 00:01:59,080 So let's talk about what a target is first then. 28 00:01:59,080 --> 00:02:03,520 So when we talk about a target what we're actually referring to is the actual storage 29 00:02:03,520 --> 00:02:04,760 device itself. 30 00:02:04,760 --> 00:02:07,880 So this can be a server that is on your local network. 31 00:02:07,880 --> 00:02:12,960 It can be a server that you're reaching over the internet or over a wide area network. 32 00:02:12,960 --> 00:02:18,719 But really this target is the storage device that is being shared that people want to make 33 00:02:18,719 --> 00:02:19,719 use of. 34 00:02:19,759 --> 00:02:24,919 And really people are going to want to reach over the network and use this storage device 35 00:02:24,919 --> 00:02:27,319 as if it was another hard disk. 36 00:02:27,319 --> 00:02:29,800 Like I say this is known as the target. 37 00:02:29,800 --> 00:02:33,639 Now who actually wants to use this storage? 38 00:02:33,639 --> 00:02:36,120 This is going to be the initiator. 39 00:02:36,120 --> 00:02:40,439 So the person who wants to make use of this storage, this SCSI storage they're going to 40 00:02:40,439 --> 00:02:44,280 act as a client and they will connect in to the target. 41 00:02:44,280 --> 00:02:49,560 So think about it like this we've got this big target right here with some SCSI configuration. 42 00:02:49,560 --> 00:02:50,560 This is the target. 43 00:02:50,560 --> 00:02:52,719 We have a little computer over here. 44 00:02:52,719 --> 00:02:54,520 This is going to be the initiator. 45 00:02:54,520 --> 00:02:59,039 The computer can make this connection to the target over the network. 46 00:02:59,039 --> 00:03:02,439 Like I say not just a physical SCSI cable. 47 00:03:02,439 --> 00:03:09,719 And the server is going to present this storage to the initiator and it will just appear locally 48 00:03:09,719 --> 00:03:12,680 on the initiator's device like another disk. 49 00:03:12,680 --> 00:03:18,920 So let's imagine before the connection the only hard drive on the initiator is SDA. 50 00:03:18,919 --> 00:03:23,679 Once they make that connection over the network, this storage will just appear like another 51 00:03:23,679 --> 00:03:26,679 disk SDB to use an example. 52 00:03:26,679 --> 00:03:32,359 Now in order for this operation to work we do need to have other information in play. 53 00:03:32,359 --> 00:03:37,759 This primarily one of the things you need to know is the WWID like I said the Worldwide 54 00:03:37,759 --> 00:03:39,159 Identifier. 55 00:03:39,159 --> 00:03:43,439 This number has to be absolutely unique throughout the entire world. 56 00:03:43,439 --> 00:03:48,839 And the reason why is that so SCSI devices that are connected to the internet can actually 57 00:03:48,840 --> 00:03:50,719 identify and separate each other. 58 00:03:50,719 --> 00:03:54,640 There are no duplicates going on here so no confusion. 59 00:03:54,640 --> 00:03:58,920 You can kind of conceptualize this as a MAC address on your PC. 60 00:03:58,920 --> 00:04:03,000 The way a MAC address is going to be unique to a physical device. 61 00:04:03,000 --> 00:04:06,920 The WWID is also going to be unique worldwide. 62 00:04:06,920 --> 00:04:13,159 Now the last thing we need to know is this concept of a LUN the logical unit number. 63 00:04:13,159 --> 00:04:20,519 This is going to be what the target i.e. the server actually uses to identify an iSCSI 64 00:04:20,519 --> 00:04:21,519 device. 65 00:04:21,519 --> 00:04:24,279 So each iSCSI device will have that LUN. 66 00:04:24,279 --> 00:04:30,639 Now one thing we want to remember here is that with respect to the WWID this has to 67 00:04:30,639 --> 00:04:32,399 be unique across the entire world. 68 00:04:32,399 --> 00:04:35,279 This is a globally unique identifier. 69 00:04:35,279 --> 00:04:41,680 Whereas when we're talking about the logical unit number this only has to be unique on 70 00:04:41,680 --> 00:04:43,600 the local network. 71 00:04:43,600 --> 00:04:48,199 Now with respect to what we were talking about we have our target here which would be our 72 00:04:48,199 --> 00:04:51,000 server and our little initiator. 73 00:04:51,000 --> 00:04:56,600 For the purposes of the L-PIC 2 examination all we really have to focus in on is understanding 74 00:04:56,600 --> 00:05:01,600 these key concepts and understanding how the initiator configuration works. 75 00:05:01,600 --> 00:05:05,360 So this is the configuration that we're going to focus in on. 76 00:05:05,360 --> 00:05:11,120 So what I shall do is I shall show you how we can install our basic initiator package. 77 00:05:11,120 --> 00:05:17,040 So what I'll have to do is the sudo apt install and it's going to be open hyphen iSCSI and 78 00:05:17,040 --> 00:05:20,160 to enter type in my password and I'll say yes. 79 00:05:20,160 --> 00:05:23,079 Okay now what I'll do is I'll just check my IP address. 80 00:05:23,079 --> 00:05:27,600 So my IP address is 192.168.0.65. 81 00:05:27,600 --> 00:05:33,199 Since I am pretending to be the initiator over here this is going to be my IP address. 82 00:05:33,199 --> 00:05:37,399 So 192.168.0.65. 83 00:05:37,399 --> 00:05:41,839 Now let's say we had a target over here and the target which was acting as the server 84 00:05:41,839 --> 00:05:49,919 effectively had an IP address of 192.168.0.99 let's just say. 85 00:05:49,919 --> 00:05:55,199 So we have our IP address here, we have the server IP address here, we would want to make 86 00:05:55,199 --> 00:06:02,039 our connection to the target and then the target can serve up over to us this LUN this 87 00:06:02,039 --> 00:06:06,799 logical unit and we can then mount this LUN on our system. 88 00:06:06,800 --> 00:06:10,600 That would just appear to us like we've just installed another hard drive. 89 00:06:10,600 --> 00:06:15,879 So the command that we could actually use to see the name of the targets that are provided 90 00:06:15,879 --> 00:06:20,120 by this iSCSI server would be as follows. 91 00:06:20,120 --> 00:06:23,960 We would say iSCSI ADM for admin. 92 00:06:23,960 --> 00:06:28,800 I'm going to say dash M for the modes and we're going to say discovery and then dash 93 00:06:28,800 --> 00:06:35,120 T for the target and we could specify a particular target that was configured on that device. 94 00:06:35,120 --> 00:06:38,280 And we just say 192.168.0.99. 95 00:06:38,280 --> 00:06:44,519 I'll just say it was called target 01 and then I would say dash P for the portal which 96 00:06:44,519 --> 00:06:49,079 would just be the address of the remote server and this is ultimately how we could see the 97 00:06:49,079 --> 00:06:52,360 targets provided by an iSCSI server. 98 00:06:52,360 --> 00:06:57,560 Now again, this part of the configuration here might be a little bit confusing. 99 00:06:57,560 --> 00:07:03,360 That is because that would actually have to be specified over on the target configuration 100 00:07:03,400 --> 00:07:07,520 which like I say is actually not part of the LPIC2 examination. 101 00:07:07,520 --> 00:07:12,800 So this actual config would actually be specified in a particular configuration file and this 102 00:07:12,800 --> 00:07:15,920 part here is just the IP address of that server. 103 00:07:15,920 --> 00:07:21,360 So really all we are focusing on is we have this iSCSI ADM command. 104 00:07:21,360 --> 00:07:26,400 We can discover particular targets, whatever their name may happen to be in that particular 105 00:07:26,400 --> 00:07:27,400 configuration file. 106 00:07:27,400 --> 00:07:29,160 We don't have to worry about that. 107 00:07:29,160 --> 00:07:34,840 And then who do we actually want to send this to, i.e. the target's IP address. 108 00:07:34,840 --> 00:07:40,520 And assuming we do have such a server that does exist which has this IP address and in 109 00:07:40,520 --> 00:07:45,280 its configuration file which we don't have to worry about, has this particular configuration 110 00:07:45,280 --> 00:07:49,360 that ultimately we would be able to discover this target. 111 00:07:49,360 --> 00:07:52,520 Now what we talked about was a simple discovery. 112 00:07:52,520 --> 00:07:58,080 Okay, we here as the initiator, we just have to send out this discovery with information 113 00:07:58,120 --> 00:08:03,039 relating to the server's IP address and whatever the server may have configured on its own 114 00:08:03,039 --> 00:08:04,399 system right here. 115 00:08:04,399 --> 00:08:06,439 But it may not be quite as simple as that. 116 00:08:06,439 --> 00:08:10,519 The server may actually require things like authentication. 117 00:08:10,519 --> 00:08:15,519 So when you try to discover its services, it's not enough for you just to type in the IP 118 00:08:15,519 --> 00:08:17,279 address or whatever it may be. 119 00:08:17,279 --> 00:08:23,120 You also may have to provide some authentication credentials as well as potentially other 120 00:08:23,120 --> 00:08:24,599 configuration settings. 121 00:08:24,720 --> 00:08:30,200 Now, what we want to be remembering for the purposes of the examination is the location 122 00:08:30,200 --> 00:08:32,320 of where we could do such a thing. 123 00:08:32,320 --> 00:08:36,680 The configuration settings for our iSCSI initiator. 124 00:08:36,680 --> 00:08:40,519 Now this is going to be in a very particular location and this is really something that 125 00:08:40,519 --> 00:08:42,080 we want to be focusing on. 126 00:08:42,080 --> 00:08:47,519 And this is going to be in, I'll say, CIDO, NANO because we're going into the Etsy directory. 127 00:08:47,519 --> 00:08:48,920 And then iSCSI. 128 00:08:48,920 --> 00:08:52,879 And then it's going to be iSCSI-D.conf. 129 00:08:53,000 --> 00:08:58,480 If I open this up right here, we can see this is the open iSCSI default configuration. 130 00:08:58,480 --> 00:09:03,159 Now we can see here how we can actually start our particular service. 131 00:09:03,159 --> 00:09:07,320 If we scroll on down, we can see we have chap settings for particular authentication. 132 00:09:07,320 --> 00:09:11,320 We can add in a authentication username, authentication passwords. 133 00:09:11,320 --> 00:09:16,879 We can have discovery session, authentication, and a whole bunch of other information relating 134 00:09:16,879 --> 00:09:19,080 to timeouts, so on, so forth. 135 00:09:19,080 --> 00:09:23,440 The actual details of this configuration file are not so much to concern. 136 00:09:23,440 --> 00:09:29,280 Just that you may have to toggle particular settings as the initiator and the location 137 00:09:29,280 --> 00:09:34,759 where you would do such a thing would be in Etsy, iSCSI, iSCSI-D.conf. 138 00:09:34,759 --> 00:09:37,080 Really try to remember those settings. 139 00:09:37,080 --> 00:09:45,360 So between the iSCSI-D.conf file and the iSCSI-ADM command, as an initiator, you can ultimately 140 00:09:45,360 --> 00:09:52,800 discover targets on a particular server that will lend to us these particular storage services 141 00:09:52,800 --> 00:09:58,600 that are being shared over a network without the need for a traditional SCSI cable connection 142 00:09:58,600 --> 00:09:59,919 between the two devices. 143 00:09:59,919 --> 00:10:04,639 All of this facilitated over the network via TCP-IP. 144 00:10:04,639 --> 00:10:08,399 And those really are the main points that we have to understand for the purposes of 145 00:10:08,399 --> 00:10:10,039 the LPIC2 examination objectives. 146 00:10:10,039 --> 00:10:14,240 OK, that looks like I hope this has been informative for you and I'd like to thank you for viewing. 147 00:10:15,360 --> 00:10:16,360 Thank you.