1
00:00:05,908 --> 00:00:10,310
- In this video, I'm going
to explain ad-hoc commands.

2
00:00:10,310 --> 00:00:11,500
In an ad-hoc command,

3
00:00:11,500 --> 00:00:14,470
Ansible modules are used
to perform specific tasks

4
00:00:14,470 --> 00:00:15,303
on managed hosts.

5
00:00:15,303 --> 00:00:17,770
An ad-hoc commands are perfect

6
00:00:17,770 --> 00:00:20,450
for running one task on a managed host.

7
00:00:20,450 --> 00:00:23,610
Some common use cases, are
for initial host set up

8
00:00:23,610 --> 00:00:27,010
for instance, that is something
that we have already covered

9
00:00:27,010 --> 00:00:30,090
in the first lesson of this course.

10
00:00:30,090 --> 00:00:32,880
Or for checking configuration on hosts,

11
00:00:32,880 --> 00:00:33,950
if you want to find out

12
00:00:33,950 --> 00:00:36,170
if a specific configuration is present,

13
00:00:36,170 --> 00:00:38,680
ad-hoc commands are the way to go.

14
00:00:38,680 --> 00:00:41,300
Also ad-hoc commands are
a perfect way to learn

15
00:00:41,300 --> 00:00:44,410
how easy Ansible really is.

16
00:00:44,410 --> 00:00:47,410
The opposite of the ad-hoc
commands is the playbook.

17
00:00:47,410 --> 00:00:50,010
The playbook is the way
to implement more complex

18
00:00:50,010 --> 00:00:53,210
tasks, where dependency
relations have to be managed.

19
00:00:53,210 --> 00:00:54,890
You may find for instance,

20
00:00:54,890 --> 00:00:57,760
that an ad-hoc command
to start your web service

21
00:00:57,760 --> 00:01:01,010
is going to fill because the
web service is not there.

22
00:01:01,010 --> 00:01:03,720
That is the use case
for creating a playbook,

23
00:01:03,720 --> 00:01:05,300
and the playbook is taking care

24
00:01:05,300 --> 00:01:08,301
of creating the entire desired state.

25
00:01:08,301 --> 00:01:11,520
In ad-hoc commands modules are used.

26
00:01:11,520 --> 00:01:13,640
An Ansible module is a python script

27
00:01:13,640 --> 00:01:16,320
that will be executed on a managed host.

28
00:01:16,320 --> 00:01:20,500
And there are over 3000
modules available in Ansible.

29
00:01:20,500 --> 00:01:25,500
Modules can be offered as such
which was pre Ansible 2.10

30
00:01:25,940 --> 00:01:28,420
or as a part of an Ansible collection,

31
00:01:28,420 --> 00:01:31,223
which you will find an
Ansible two 2.10 and later.

32
00:01:32,730 --> 00:01:35,730
Now, how do we run these ad-hoc commands?

33
00:01:35,730 --> 00:01:37,930
Well, you use the Ansible commands

34
00:01:37,930 --> 00:01:39,750
to run the ad-hoc commands.

35
00:01:39,750 --> 00:01:41,880
And while running the Ansible commands,

36
00:01:41,880 --> 00:01:44,220
an inventory must be present,

37
00:01:44,220 --> 00:01:47,250
you must specify which hosts to address.

38
00:01:47,250 --> 00:01:49,349
You will also use a -m option to address

39
00:01:49,349 --> 00:01:53,900
specific module, a -a
for the module arguments.

40
00:01:53,900 --> 00:01:55,120
An example for instance

41
00:01:55,120 --> 00:01:57,713
is Ansible - i inventory windows,

42
00:01:58,640 --> 00:02:00,740
which is addressing a host

43
00:02:00,740 --> 00:02:04,893
with the name windows- m
ansible.windows.win_ping,

44
00:02:06,860 --> 00:02:08,860
which is the Ansible collection name

45
00:02:08,860 --> 00:02:11,320
of the module that you are going to use,

46
00:02:11,320 --> 00:02:13,000
to ping the windows host.

47
00:02:13,000 --> 00:02:18,000
Or ansible- i inventory all
which is addressing all hosts,

48
00:02:18,470 --> 00:02:22,940
- m ansible.builtin.command-a reboot,

49
00:02:22,940 --> 00:02:26,300
which is going to use the command module,

50
00:02:26,300 --> 00:02:28,160
and this command module,

51
00:02:28,160 --> 00:02:31,310
as it is executing
arbitrary Linux commands

52
00:02:31,310 --> 00:02:34,153
is next going to issue the
Linux a reboot commands.

53
00:02:35,060 --> 00:02:36,170
Or for instance,

54
00:02:36,170 --> 00:02:40,970
ansible-i inventory rocky1-m
ansible.builtin.user,

55
00:02:40,970 --> 00:02:43,480
which is using the user
module on the host,

56
00:02:43,480 --> 00:02:48,120
with the name rocky1- a name
is anna state is present

57
00:02:48,120 --> 00:02:49,680
which is going to make sure

58
00:02:49,680 --> 00:02:51,910
that this specific user is present.

59
00:02:51,910 --> 00:02:53,113
Let's go check this out,

60
00:02:55,430 --> 00:02:58,500
right, let's run one example,

61
00:02:58,500 --> 00:03:02,360
ansible-i inventory all.

62
00:03:02,360 --> 00:03:04,830
So we are going to run against all host

63
00:03:04,830 --> 00:03:09,287
- m ansible.builtin.command-a reboot.

64
00:03:12,770 --> 00:03:15,943
Well, no, let's do another, -a id.

65
00:03:21,060 --> 00:03:23,120
There we can see that the id command

66
00:03:23,120 --> 00:03:25,210
is giving us some results.

67
00:03:25,210 --> 00:03:27,430
Now, the reason I wanted to do the id

68
00:03:27,430 --> 00:03:29,113
before the reboot is this.

69
00:03:30,940 --> 00:03:33,240
do you see that connection
refused connection

70
00:03:33,240 --> 00:03:36,280
refused, reachable through.

71
00:03:36,280 --> 00:03:37,160
Now why is that?

72
00:03:37,160 --> 00:03:41,000
That is because Ansible is
running the reboot command,

73
00:03:41,000 --> 00:03:43,360
then it's requesting status information

74
00:03:43,360 --> 00:03:46,358
and it can't because it is rebooting.

75
00:03:46,358 --> 00:03:49,760
So once the hosts are back,

76
00:03:49,760 --> 00:03:53,900
then we can use a command
like uptime for instance,

77
00:03:53,900 --> 00:03:58,813
to verify that the hosts
have successfully rebooted.

78
00:04:00,050 --> 00:04:02,160
As you can see up zero minutes,

79
00:04:02,160 --> 00:04:04,080
zero minutes, zero minutes.

80
00:04:04,080 --> 00:04:07,920
Another example is ansible-i inventory.

81
00:04:07,920 --> 00:04:10,810
Do we really need minus i inventory?

82
00:04:10,810 --> 00:04:11,953
Let's go check it out,

83
00:04:11,953 --> 00:04:15,440
ansible.cfg as inventory, is inventory

84
00:04:15,440 --> 00:04:19,410
which means that ansible.cfg
is going to look for a file

85
00:04:19,410 --> 00:04:21,800
with name inventory in
the current directory.

86
00:04:21,800 --> 00:04:24,020
So we can make this comment
a little bit shorter,

87
00:04:24,020 --> 00:04:29,020
ansible on rocky-m
ansible.builtin.dot.user -a name=anna

88
00:04:37,590 --> 00:04:39,803
state=present,

89
00:04:43,830 --> 00:04:47,120
and oops that's a so called typo.

90
00:04:47,120 --> 00:04:48,880
Let's fix the typo and run it again,

91
00:04:48,880 --> 00:04:52,040
and now we can see it
is giving us a change

92
00:04:52,040 --> 00:04:55,710
which means a user anna did not yet exist.

93
00:04:55,710 --> 00:04:58,830
Now, here we have used FQCN

94
00:04:58,830 --> 00:05:01,570
the fully qualified collection names.

95
00:05:01,570 --> 00:05:04,820
How about we just use the module name,

96
00:05:04,820 --> 00:05:07,240
there you can see that on Ansible 2.9

97
00:05:07,240 --> 00:05:09,940
that is perfectly working as well.

98
00:05:09,940 --> 00:05:12,390
The future is collections, but as long

99
00:05:12,390 --> 00:05:14,800
as you are on Ansible 2.9, you will find

100
00:05:14,800 --> 00:05:17,883
that the module names
themselves will also work.