1 00:00:00,050 --> 00:00:00,990 In this lesson, 2 00:00:00,990 --> 00:00:02,790 we're going to discuss repositories, 3 00:00:02,790 --> 00:00:05,400 because most of the software packages that you're going to use 4 00:00:05,400 --> 00:00:08,340 are going to be acquired from those repositories. 5 00:00:08,340 --> 00:00:09,360 Now, most packages 6 00:00:09,360 --> 00:00:12,210 are included in the official distribution repositories, 7 00:00:12,210 --> 00:00:15,120 but there's also cases where packages can't be installed 8 00:00:15,120 --> 00:00:16,320 due to dependencies, 9 00:00:16,320 --> 00:00:17,340 and you're going to need to install 10 00:00:17,340 --> 00:00:19,050 all the dependencies manually, 11 00:00:19,050 --> 00:00:21,060 so you may have to create your own repository 12 00:00:21,060 --> 00:00:23,130 and deploy your packages from it. 13 00:00:23,130 --> 00:00:25,080 Knowing which repositories you're using 14 00:00:25,080 --> 00:00:26,610 can also help you understand 15 00:00:26,610 --> 00:00:28,740 how your system is managing its updates. 16 00:00:28,740 --> 00:00:32,040 So let's go ahead and discuss how you configure repositories 17 00:00:32,040 --> 00:00:35,680 using various local command line tools to meet your needs. 18 00:00:35,680 --> 00:00:38,010 Repositories, also known as repos, 19 00:00:38,010 --> 00:00:41,220 are storage locations for available software packages. 20 00:00:41,220 --> 00:00:43,530 Now, repositories are checked by package managers, 21 00:00:43,530 --> 00:00:45,900 like YUM, DNF, and APT, 22 00:00:45,900 --> 00:00:48,570 whenever you're installing or upgrading software. 23 00:00:48,570 --> 00:00:50,520 There are three kinds of repositories 24 00:00:50,520 --> 00:00:51,660 that you're going to find. 25 00:00:51,660 --> 00:00:53,520 These are local repositories, 26 00:00:53,520 --> 00:00:57,450 centralized internal repositories, and vendor repositories. 27 00:00:57,450 --> 00:00:58,590 Local repositories 28 00:00:58,590 --> 00:01:01,290 are stored on the system's local storage drive. 29 00:01:01,290 --> 00:01:02,610 Installation is easy, 30 00:01:02,610 --> 00:01:05,220 but version control is much more difficult 31 00:01:05,220 --> 00:01:06,870 because of the decentralized nature 32 00:01:06,870 --> 00:01:08,880 of these local repositories. 33 00:01:08,880 --> 00:01:11,400 If you manage 20 Linux servers, for example, 34 00:01:11,400 --> 00:01:13,230 each one is going to have its own repository 35 00:01:13,230 --> 00:01:14,910 that you have to maintain. 36 00:01:14,910 --> 00:01:17,070 Instead, you might move to a centralized 37 00:01:17,070 --> 00:01:18,750 internal repository. 38 00:01:18,750 --> 00:01:20,700 These centralized internal repositories 39 00:01:20,700 --> 00:01:22,650 are stored on one or more systems 40 00:01:22,650 --> 00:01:24,870 within your internal local area network, 41 00:01:24,870 --> 00:01:27,630 and they're managed by a Linux system administrator. 42 00:01:27,630 --> 00:01:30,900 This centralized approach makes version control much simpler 43 00:01:30,900 --> 00:01:32,490 across your organization. 44 00:01:32,490 --> 00:01:35,520 So again, let's say you're managing 20 Linux servers, 45 00:01:35,520 --> 00:01:39,540 one can host all the repositories for all the other 19. 46 00:01:39,540 --> 00:01:42,720 This way, that one server is your central repository 47 00:01:42,720 --> 00:01:44,730 internal to your own local area network, 48 00:01:44,730 --> 00:01:47,460 and all of your Linux servers will go to that server 49 00:01:47,460 --> 00:01:49,500 to download their packages from it. 50 00:01:49,500 --> 00:01:52,890 Now, the third type we have is known as a vendor repository. 51 00:01:52,890 --> 00:01:54,660 These are maintained on the internet, 52 00:01:54,660 --> 00:01:57,420 often by the distribution vendor themself. 53 00:01:57,420 --> 00:01:59,910 Version control here is very difficult though, 54 00:01:59,910 --> 00:02:01,470 because the vendor gets to decide 55 00:02:01,470 --> 00:02:03,810 what package versions are being made available 56 00:02:03,810 --> 00:02:08,070 to everyone in the world inside of their vendor repository. 57 00:02:08,070 --> 00:02:10,620 Therefore, if you're working as a Linux system administrator 58 00:02:10,620 --> 00:02:13,050 on an enterprise network, most of the time, 59 00:02:13,050 --> 00:02:14,820 you're going to find that you're using a centralized 60 00:02:14,820 --> 00:02:16,290 internal repository. 61 00:02:16,290 --> 00:02:17,460 That way, you can control 62 00:02:17,460 --> 00:02:19,590 exactly what versions are being used 63 00:02:19,590 --> 00:02:21,750 on all of your Linux servers. 64 00:02:21,750 --> 00:02:23,850 Now, system administrators can also designate 65 00:02:23,850 --> 00:02:26,850 a specific location as a yum repository 66 00:02:26,850 --> 00:02:29,400 to be able to create this internal repository. 67 00:02:29,400 --> 00:02:32,910 To do this, you're going to use the createrepo command. 68 00:02:32,910 --> 00:02:35,250 This command is going to update the XML files 69 00:02:35,250 --> 00:02:38,100 that are used to reference the repository's location. 70 00:02:38,100 --> 00:02:41,040 This repository might be on the local storage drive, 71 00:02:41,040 --> 00:02:42,870 which is going to be a local repository, 72 00:02:42,870 --> 00:02:45,870 or it could be available from an Apache web server, 73 00:02:45,870 --> 00:02:48,990 which becomes a centralized internal repository. 74 00:02:48,990 --> 00:02:51,240 After running the createrepo command, 75 00:02:51,240 --> 00:02:55,440 a .repo or repo configuration file is going to be created 76 00:02:55,440 --> 00:02:57,150 and that provides additional information 77 00:02:57,150 --> 00:02:58,860 about your repository. 78 00:02:58,860 --> 00:03:00,960 The .repo files are going to be stored 79 00:03:00,960 --> 00:03:05,910 in the /etc/yum.repos.d/ directory. 80 00:03:05,910 --> 00:03:08,190 Some of the components of the .repo file 81 00:03:08,190 --> 00:03:11,250 include the bracket repo-name bracket, 82 00:03:11,250 --> 00:03:13,650 which is going to refer to the repository name. 83 00:03:13,650 --> 00:03:15,570 name=Repository Name, 84 00:03:15,570 --> 00:03:18,330 which refers to the human-friendly name of that repo. 85 00:03:18,330 --> 00:03:21,960 baseurl=, which refers to the path to the repo. 86 00:03:21,960 --> 00:03:25,200 enabled=1, which basically enables the repo. 87 00:03:25,200 --> 00:03:27,780 If you set this to zero, it will disable the repo. 88 00:03:27,780 --> 00:03:32,460 And gpgcheck=0, which disables GPG checking, 89 00:03:32,460 --> 00:03:34,890 which is a form of encryption in digital certificates. 90 00:03:34,890 --> 00:03:37,650 If you want to enable this, you could set this to one. 91 00:03:37,650 --> 00:03:39,780 Another yum repository configuration file 92 00:03:39,780 --> 00:03:43,410 is located at /etc/yum.conf, 93 00:03:43,410 --> 00:03:44,430 so you should also look at that 94 00:03:44,430 --> 00:03:46,410 to ensure it's configured correctly. 95 00:03:46,410 --> 00:03:48,630 If you're using DNF as your package manager, 96 00:03:48,630 --> 00:03:53,400 you should also check the /etc/dnf/dnf.conf file, 97 00:03:53,400 --> 00:03:54,990 because it contains the configurations 98 00:03:54,990 --> 00:03:57,720 for your repositories when using DNF. 99 00:03:57,720 --> 00:03:58,800 Now, the yum command 100 00:03:58,800 --> 00:04:00,690 also includes some additional sub commands 101 00:04:00,690 --> 00:04:03,150 for viewing and using repositories. 102 00:04:03,150 --> 00:04:06,390 If you use yum repolist, this is going to be used 103 00:04:06,390 --> 00:04:08,670 to see all of the available repositories. 104 00:04:08,670 --> 00:04:10,920 If you use yum makecache, 105 00:04:10,920 --> 00:04:13,050 this is going to be used to locally cache information 106 00:04:13,050 --> 00:04:15,150 about the available repositories. 107 00:04:15,150 --> 00:04:17,339 And if you use yum clean all, 108 00:04:17,339 --> 00:04:18,390 this command is going to be used 109 00:04:18,390 --> 00:04:20,760 to clear all the out-of-date cache information 110 00:04:20,760 --> 00:04:22,860 so you can download a new copy. 111 00:04:22,860 --> 00:04:24,780 Yum also enables the synchronization 112 00:04:24,780 --> 00:04:28,020 of an online repository to a local storage location too, 113 00:04:28,020 --> 00:04:29,280 if you want to. 114 00:04:29,280 --> 00:04:30,990 This is known as mirroring, 115 00:04:30,990 --> 00:04:33,390 and it has the advantage of reducing the way-in traffic 116 00:04:33,390 --> 00:04:35,010 and lessening the time to load things 117 00:04:35,010 --> 00:04:37,110 from the parent repository. 118 00:04:37,110 --> 00:04:39,960 This is done by using the reposync utility. 119 00:04:39,960 --> 00:04:41,940 The reposync utility is going to be used 120 00:04:41,940 --> 00:04:44,280 to manage this synchronization process, 121 00:04:44,280 --> 00:04:45,600 and you can choose to synchronize 122 00:04:45,600 --> 00:04:47,400 the parent repository once, 123 00:04:47,400 --> 00:04:50,100 or you can cause it to update periodically. 124 00:04:50,100 --> 00:04:52,470 For example, you as a system administrator 125 00:04:52,470 --> 00:04:54,960 might want to synchronize the Red Hat Network 126 00:04:54,960 --> 00:04:59,220 or RHN repository over to a local server that you control. 127 00:04:59,220 --> 00:05:01,440 This then enables internal Red Hat servers 128 00:05:01,440 --> 00:05:03,780 to use the local server as a repository, 129 00:05:03,780 --> 00:05:05,400 instead of having to go over the internet 130 00:05:05,400 --> 00:05:08,340 to the Red Hat Networks repository itself. 131 00:05:08,340 --> 00:05:11,130 To do this, simply run the reposync command 132 00:05:11,130 --> 00:05:14,010 by typing reposync and the options. 133 00:05:14,010 --> 00:05:15,570 Like the yum package manager, 134 00:05:15,570 --> 00:05:18,300 the APT package manager can also be configured 135 00:05:18,300 --> 00:05:19,500 to access repositories 136 00:05:19,500 --> 00:05:21,870 as part of the software management life cycle. 137 00:05:21,870 --> 00:05:24,990 The repositories are going to be configured for APT 138 00:05:24,990 --> 00:05:29,990 inside the /etc/apt/sources.list file, 139 00:05:30,390 --> 00:05:35,390 and in the /etc/apt/sources.list.d/ directory. 140 00:05:37,230 --> 00:05:40,140 Like the yum repositories, APT repositories 141 00:05:40,140 --> 00:05:42,630 are also going to be able to be on the local system, 142 00:05:42,630 --> 00:05:43,800 on a local network, 143 00:05:43,800 --> 00:05:46,980 or hosted on the internet by a vendor. 144 00:05:46,980 --> 00:05:49,800 When it comes to configuring your APT package manager, 145 00:05:49,800 --> 00:05:52,200 you do want to check the configuration files for that 146 00:05:52,200 --> 00:05:55,560 under /etc/apt.conf, 147 00:05:55,560 --> 00:05:57,150 which contains the configuration file 148 00:05:57,150 --> 00:05:58,833 for your APT package manager.