1 00:00:02,380 --> 00:00:04,320 Now, there is more we can do 2 00:00:04,320 --> 00:00:08,840 with the docker command than with containers and images. 3 00:00:08,840 --> 00:00:13,300 We already saw a couple of different commands and action 4 00:00:13,300 --> 00:00:18,110 and I wanna come back to this mode which we have here 5 00:00:18,110 --> 00:00:21,810 when we restarted a container and the mode which we had 6 00:00:21,810 --> 00:00:24,043 when we initially started a container. 7 00:00:24,950 --> 00:00:26,930 Here, when we're restarting it 8 00:00:26,930 --> 00:00:31,930 the process in our terminal here finished immediately. 9 00:00:32,150 --> 00:00:35,777 We're not attached to this running docker container 10 00:00:35,777 --> 00:00:38,610 in the terminal anymore. 11 00:00:38,610 --> 00:00:42,100 Nonetheless, it clearly is still running 12 00:00:42,100 --> 00:00:44,530 as we can see with docker ps. 13 00:00:44,530 --> 00:00:48,710 So, this container is running, it's just not blocking us 14 00:00:48,710 --> 00:00:52,330 here in the terminal and that's different compared 15 00:00:52,330 --> 00:00:55,950 to the docker run command we executed before. 16 00:00:55,950 --> 00:01:00,090 If I run this again, binding to a different local port 17 00:01:00,090 --> 00:01:04,260 since 3000 is already used by the already running container 18 00:01:04,260 --> 00:01:06,030 but if I use a different port here 19 00:01:06,030 --> 00:01:08,850 I'm starting a new additional container 20 00:01:08,850 --> 00:01:13,680 based on the same image, so, therefore with docker ps 21 00:01:13,680 --> 00:01:15,470 in a different terminal here 22 00:01:15,470 --> 00:01:18,140 we see we got two containers up and running now 23 00:01:20,260 --> 00:01:23,650 but you see that for docker run, we're stuck 24 00:01:23,650 --> 00:01:27,080 in this process, I can't enter more commands here. 25 00:01:27,080 --> 00:01:29,830 I mean, I can type but I can't commit them. 26 00:01:29,830 --> 00:01:32,260 I can't confirm them with enter 27 00:01:32,260 --> 00:01:35,570 instead, this process is blocking this terminal 28 00:01:36,470 --> 00:01:39,700 and with docker start that was not the case. 29 00:01:39,700 --> 00:01:43,500 Now, this is not a blog or anything you have to accept 30 00:01:43,500 --> 00:01:47,440 this is something you can configure if you wanna be 31 00:01:47,440 --> 00:01:51,683 in this attached mode or in detached mode. 32 00:01:52,540 --> 00:01:56,570 And it's just a case that for starting with docker start 33 00:01:56,570 --> 00:02:00,840 the detached mode is the default for running with docker run 34 00:02:00,840 --> 00:02:03,760 the attached mode is the default. 35 00:02:03,760 --> 00:02:07,330 And now the question of course is which mode do you want 36 00:02:07,330 --> 00:02:09,539 and why does this even matter? 37 00:02:09,539 --> 00:02:12,880 Well, in this example application, I am logging 38 00:02:12,880 --> 00:02:16,923 something to the console whenever we set a new goal. 39 00:02:18,380 --> 00:02:23,380 So, here if I add, Learn Docker in-depth! as a goal 40 00:02:23,660 --> 00:02:27,680 on local host 3000, that's my started container 41 00:02:27,680 --> 00:02:32,680 which was detached, we see nothing in the console anywhere. 42 00:02:35,050 --> 00:02:38,460 On the other hand, if I go to local host 8,000 43 00:02:38,460 --> 00:02:42,710 which is that new container, we run with docker run 44 00:02:42,710 --> 00:02:46,180 and I set my goal here 45 00:02:48,050 --> 00:02:52,470 you will see that it also shows up into terminal here 46 00:02:52,470 --> 00:02:56,100 because here we're attached to this running container 47 00:02:56,100 --> 00:03:00,210 and attached simply means that we're listening to the output 48 00:03:00,210 --> 00:03:01,370 of that container. 49 00:03:01,370 --> 00:03:04,970 For example, to what's being printed to the console 50 00:03:05,850 --> 00:03:09,560 and this might or might not be what we want. 51 00:03:09,560 --> 00:03:12,350 We can also run a container in detached mode 52 00:03:12,350 --> 00:03:15,670 if we want to, we don't have to accept that default 53 00:03:15,670 --> 00:03:17,270 of being attached. 54 00:03:17,270 --> 00:03:20,800 For this, I'll quickly stop this more recent container 55 00:03:20,800 --> 00:03:23,240 which I started with docker stop 56 00:03:23,240 --> 00:03:25,420 which will take a couple of seconds 57 00:03:25,420 --> 00:03:28,480 so, that's the container we started with docker run 58 00:03:29,490 --> 00:03:32,940 and once this is stopped, I will re-run it 59 00:03:32,940 --> 00:03:37,940 but now in detached mode by adding -d as an extra flag 60 00:03:38,060 --> 00:03:39,740 in front of the image ID here 61 00:03:41,020 --> 00:03:44,700 if, I now enter it you see, now I just get the ID 62 00:03:44,700 --> 00:03:48,300 the automatically generated ID of the new container 63 00:03:48,300 --> 00:03:52,040 you see with docker ps that we have this container up 64 00:03:52,040 --> 00:03:56,170 and running that still shortened ID off that up 65 00:03:56,170 --> 00:03:58,050 and running container by the way 66 00:03:58,050 --> 00:03:59,880 and we see that container is running 67 00:03:59,880 --> 00:04:04,010 and therefor visiting local host 8,000 also works. 68 00:04:04,010 --> 00:04:07,890 But now if I Learn Docker in-depth! 69 00:04:07,890 --> 00:04:10,990 for example, here on local host 8,000 70 00:04:12,090 --> 00:04:14,520 we don't see that log into terminal 71 00:04:14,520 --> 00:04:17,149 where we execute a docker run 72 00:04:17,149 --> 00:04:19,959 because now we're not attached to the output 73 00:04:19,959 --> 00:04:24,960 since we used the -d flag to start in detach mode. 74 00:04:25,060 --> 00:04:27,520 The advantages that we now can use one 75 00:04:27,520 --> 00:04:30,920 and the same terminal to also do other things. 76 00:04:30,920 --> 00:04:34,550 If you still wanna look into your running container 77 00:04:34,550 --> 00:04:36,990 you got two ways of doing that. 78 00:04:36,990 --> 00:04:39,920 For one, we can see with docker help 79 00:04:41,730 --> 00:04:44,830 that there is an attached command. 80 00:04:44,830 --> 00:04:48,870 So, we can attach ourselves again to a running container. 81 00:04:48,870 --> 00:04:52,870 We can simply find the container and use its name 82 00:04:52,870 --> 00:04:57,720 or its ID both works and then run docker attach 83 00:04:57,720 --> 00:05:01,280 and that name and we are attached again 84 00:05:01,280 --> 00:05:04,830 and therefore now, if we change it again 85 00:05:07,660 --> 00:05:12,463 and set a new goal, we do see this output again. 86 00:05:13,560 --> 00:05:15,140 So, that's one way of doing it 87 00:05:16,140 --> 00:05:19,590 but actually let me stop this container again 88 00:05:22,110 --> 00:05:26,600 and let me restart it thereafter 89 00:05:26,600 --> 00:05:28,630 now in detached mode automatically 90 00:05:28,630 --> 00:05:31,340 since that is the default for docker start 91 00:05:31,340 --> 00:05:34,100 and let me show you another way of getting access to 92 00:05:34,100 --> 00:05:37,580 for example, the log messages that are printed inside 93 00:05:37,580 --> 00:05:38,423 of a container. 94 00:05:39,650 --> 00:05:40,950 This is running again. 95 00:05:40,950 --> 00:05:43,900 If I now type Learn Docker in-depth! here 96 00:05:43,900 --> 00:05:47,370 and commit this, so I save this and set this goal 97 00:05:47,370 --> 00:05:49,540 we don't see the goal because we are detached 98 00:05:49,540 --> 00:05:53,750 and we could attach again to see future log messages 99 00:05:53,750 --> 00:05:57,970 or another thing we can do another useful command 100 00:05:57,970 --> 00:06:02,180 is the docker logs command which fetches the logs 101 00:06:02,180 --> 00:06:04,193 that were printed by a container. 102 00:06:05,400 --> 00:06:09,440 And here we can first of all, find the container 103 00:06:09,440 --> 00:06:11,880 eloquent_brown is the name of the container 104 00:06:11,880 --> 00:06:13,390 I'm interested here 105 00:06:13,390 --> 00:06:16,380 and then we can run docker logs on that container 106 00:06:16,380 --> 00:06:19,620 and we see the past logs that were printed 107 00:06:19,620 --> 00:06:21,760 by that container. 108 00:06:21,760 --> 00:06:26,760 We can also, if we inspect the options of docker logs 109 00:06:27,100 --> 00:06:32,100 enter follow mode by adding -f to keep on listening. 110 00:06:32,730 --> 00:06:35,510 So, basically we're now attaching ourselves again. 111 00:06:35,510 --> 00:06:38,230 So, if I add -f here, we again get 112 00:06:38,230 --> 00:06:42,330 this attached process where we see future logs 113 00:06:42,330 --> 00:06:45,363 future output by that container again. 114 00:06:46,350 --> 00:06:48,880 So, these are the different options we have for that. 115 00:06:48,880 --> 00:06:51,520 And I'm spending a lot of time on that 116 00:06:51,520 --> 00:06:54,230 because it is important that you understand 117 00:06:54,230 --> 00:06:57,450 the difference between a running and a stopped container 118 00:06:57,450 --> 00:07:00,610 and an attached and a detached container. 119 00:07:00,610 --> 00:07:02,840 No matter if it's attached or detached 120 00:07:02,840 --> 00:07:06,300 it's still up and running but if you then need information 121 00:07:06,300 --> 00:07:09,620 from inside the container, you can use docker logs 122 00:07:09,620 --> 00:07:12,370 or attach yourself to the container again 123 00:07:12,370 --> 00:07:14,463 to get that extra information. 124 00:07:16,870 --> 00:07:19,530 Now ,with that I will again 125 00:07:21,620 --> 00:07:23,800 docker stop eloquent_brown 126 00:07:24,690 --> 00:07:28,833 to bring down that container and detach myself again here. 127 00:07:29,700 --> 00:07:34,040 Now, one last note about all of that, if you would want 128 00:07:34,040 --> 00:07:38,370 to restart a stopped container like eloquent_brown here 129 00:07:39,390 --> 00:07:42,010 in attached mode, right from the start 130 00:07:42,010 --> 00:07:46,370 you can do, so by adding the -a flag to the start command. 131 00:07:46,370 --> 00:07:48,843 Now, you start this in attached mode.