Create Linux User with ssh key

If you are not using configuration automation tools like Puppet or Chef on simple Linux environment, script below will definitely simplify your Linux user creation process, especially when you have more than 10 new users to create in a row.

It will also take care of ssh key insertion to user profile, the most common issues I often encounter, during user creation with ssh key, was mixing up authorized_keys file permission and ownership between root and actual user itself since some account switch is needed.

I hope the script below would help some of you out there, making your daily sysadmin jobs simpler and more fun.

#/bin/bash

while getopts u:c:s: option

do

        case "${option}"

        in

                u) USER=${OPTARG};;

                c) CERT=${OPTARG};;

                s) SUDO=${OPTARG};;

        esac

done

echo "$CERT";

adduser $USER;

if [ "$SUDO" == "y" ]

then

        touch /etc/sudoers.d/$USER;

        echo "$USER ALL=(ALL:ALL) ALL" > /etc/sudoers.d/$USER;

        echo User added to root;

fi

su -c  'mkdir -p ~/.ssh && touch ~/.ssh/authorized_keys && chmod 700  ~/.ssh && chmod 600  ~/.ssh/authorized_keys' - $USER;

echo  "$CERT" > /home/$USER/.ssh/authorized_keys

passwd $USER;

Sample command

./adduser.sh -u myuser -s y  -c 'ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDpjky6uTgUa9eRdG/hOxjQvWDbHzw/AVVsvJmMYxwwaLBgUtESRNXEMiF56qIxxxxxxxxxxxxlzbuOLmCrM29mlyujKdqkbr8z75aWYzhT+UIma5BuEX6kLyo9LYMm4RXGsbbnfHYrvTJo1FAnzRL/LYH8ewtmvzVTauHP/k1jYbp0Q3jQgf7p1ZDssAf5vDe1sMLwaXMGUNqNKCwjjePxOxIWzQksOCjHv/ myuser@gmail.com'


Note:
- Avoid creating user with the character dot ".", else system will fail to pickup sudoers file setting.
- Script above only tested on Redhat, Amazon Linux, CentOS but not on Debian platform.

AWS OpsWorks FAQ and common commands

To create a deploy via CLI

Before using the command, you will need to first setup AWS cli on your computer, use the official AWS guide here

$ aws opsworks --region us-east-1 create-deployment --stack-id 9xxxx3-xxxx-455f-bc5c-8xxxx7a --app-id 090xxx88-2d32-xxxx-a460-faaxxxd7 --command "{ \"Name\": \"deploy\" }"

Note: AWS OpsWorks supports only one endpoint, opsworks.us-east-1.amazonaws.com (HTTPS), so you must connect to that endpoint. You can then use the API to direct AWS OpsWorks to create stacks in any AWS Region. Source

The following message will be returned if command issued accepted.

----------------------------------------------------------
|                    CreateDeployment                    |
+---------------+----------------------------------------+
|  DeploymentId |  912b37aa-f423-4dda-9966-021680bbc1a8  |

+---------------+----------------------------------------+

===================================================================================

To Create and Schedule a time-based instance via CLI

Below sample command will create a time-based instance, stack-id, layers-ids, instance type are mondoroty

aws opsworks --region us-east-1 create-instance --stack-id 58af7c69-xxxx-xxxx-8e6a-7660d7a18e55 --layer-ids 6e876603-ac96-4714-89a0-2453e1dc06f0 --os Custom --ami-id ami-6d1b343f --instance-type t2.medium --subnet-id subnet-1ae9f56e --auto-scaling-type timer --ssh-key-name sysadmin

Next, You will need to assign scheduler to wake or shut instance off, here's the sample command. The command will schedule instance 064c0869-xxxx-xxxx-9728-53d271c4a484 to power on between 00800 to 1900GMT+8 from Monday to Friday. Saturday and Sunday is included in the command to override any schedule on previously set to ON

I personally find that the command is not so user friendly as you will need to include each and every hour slot into the command.

aws opsworks  set-time-based-auto-scaling --region us-east-1 --instance-id "064c0869-xxxx-xxxx-9728-53d271c4a484" --auto-scaling-schedule "{\"Monday\": {\"0\": \"on\", \"1\": \"on\", \"2\": \"on\", \"3\": \"on\", \"4\": \"on\", \"5\": \"on\", \"6\": \"on\", \"7\": \"on\", \"8\": \"on\", \"9\": \"on\", \"10\": \"on\", \"11\": \"off\", \"12\": \"off\", \"13\": \"off\", \"14\": \"off\", \"15\": \"off\", \"16\": \"off\", \"17\": \"off\", \"18\": \"off\", \"19\": \"off\", \"20\": \"off\", \"21\": \"off\", \"22\": \"off\", \"23\": \"off\"}, \"Tuesday\": {\"0\": \"on\", \"1\": \"on\", \"2\": \"on\", \"3\": \"on\", \"4\": \"on\", \"5\": \"on\", \"6\": \"on\", \"7\": \"on\", \"8\": \"on\", \"9\": \"on\", \"10\": \"on\", \"11\": \"off\", \"12\": \"off\", \"13\": \"off\", \"14\": \"off\", \"15\": \"off\", \"16\": \"off\", \"17\": \"off\", \"18\": \"off\", \"19\": \"off\", \"20\": \"off\", \"21\": \"off\", \"22\": \"off\", \"23\": \"off\"}, \"Wednesday\": {\"0\": \"on\", \"1\": \"on\", \"2\": \"on\", \"3\": \"on\", \"4\": \"on\", \"5\": \"on\", \"6\": \"on\", \"7\": \"on\", \"8\": \"on\", \"9\": \"on\", \"10\": \"on\", \"11\": \"off\", \"12\": \"off\", \"13\": \"off\", \"14\": \"off\", \"15\": \"off\", \"16\": \"off\", \"17\": \"off\", \"18\": \"off\", \"19\": \"off\", \"20\": \"off\", \"21\": \"off\", \"22\": \"off\", \"23\": \"off\"}, \"Thursday\": {\"0\": \"on\", \"1\": \"on\", \"2\": \"on\", \"3\": \"on\", \"4\": \"on\", \"5\": \"on\", \"6\": \"on\", \"7\": \"on\", \"8\": \"on\", \"9\": \"on\", \"10\": \"on\", \"11\": \"off\", \"12\": \"off\", \"13\": \"off\", \"14\": \"off\", \"15\": \"off\", \"16\": \"off\", \"17\": \"off\", \"18\": \"off\", \"19\": \"off\", \"20\": \"off\", \"21\": \"off\", \"22\": \"off\", \"23\": \"off\"}, \"Friday\": {\"0\": \"on\", \"1\": \"on\", \"2\": \"on\", \"3\": \"on\", \"4\": \"on\", \"5\": \"on\", \"6\": \"on\", \"7\": \"on\", \"8\": \"on\", \"9\": \"on\", \"10\": \"on\", \"11\": \"off\", \"12\": \"off\", \"13\": \"off\", \"14\": \"off\", \"15\": \"off\", \"16\": \"off\", \"17\": \"off\", \"18\": \"off\", \"19\": \"off\", \"20\": \"off\", \"21\": \"off\", \"22\": \"off\", \"23\": \"off\"}, \"Saturday\": {\"0\": \"off\", \"1\": \"off\", \"2\": \"off\", \"3\": \"off\", \"4\": \"off\", \"5\": \"off\", \"6\": \"off\", \"7\": \"off\", \"8\": \"off\", \"9\": \"off\", \"10\": \"off\", \"11\": \"off\", \"12\": \"off\", \"13\": \"off\", \"14\": \"off\", \"15\": \"off\", \"16\": \"off\", \"17\": \"off\", \"18\": \"off\", \"19\": \"off\", \"20\": \"off\", \"21\": \"off\", \"22\": \"off\", \"23\": \"off\"}, \"Sunday\": {\"0\": \"off\", \"1\": \"off\", \"2\": \"off\", \"3\": \"off\", \"4\": \"off\", \"5\": \"off\", \"6\": \"off\", \"7\": \"off\", \"8\": \"off\", \"9\": \"off\", \"10\": \"off\", \"11\": \"off\", \"12\": \"off\", \"13\": \"off\", \"14\": \"off\", \"15\": \"off\", \"16\": \"off\", \"17\": \"off\", \"18\": \"off\", \"19\": \"off\", \"20\": \"off\", \"21\": \"off\", \"22\": \"off\", \"23\": \"off\"}}"

Command to show instance detail
aws opsworks --region us-east-1 describe-time-based-auto-scaling --instance-id 398913d7-ea3e-xxxx-xxxx-44ffc8befa46

Output:-
-------------------------------------------------------------------------------------
|                           DescribeTimeBasedAutoScaling                            |
+-----------------------------------------------------------------------------------+
||                       TimeBasedAutoScalingConfigurations                        ||
|+---------------------------------------------------------------------------------+|
||                                   InstanceId                                    ||
|+---------------------------------------------------------------------------------+|
||  398913d7-ea3e-4c91-9b16-44ffc8befa46                                           ||
|+---------------------------------------------------------------------------------+|
|||                              AutoScalingSchedule                              |||
||+-------------------------------------------------------------------------------+||
||||                                   Friday                                    ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  0  |  1   | 10   |  2   |  3   |  4   |  5   |  6   |  7   |   8   |   9   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  on |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on   |  on   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||                                   Monday                                    ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  0  |  1   | 10   |  2   |  3   |  4   |  5   |  6   |  7   |   8   |   9   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  on |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on   |  on   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||                                  Saturday                                   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  0  |  1   | 10   |  2   |  3   |  4   |  5   |  6   |  7   |   8   |   9   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  off|  off |  off |  off |  off |  off |  off |  off |  off |  off  |  off  ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||                                   Sunday                                    ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  0  |  1   | 10   |  2   |  3   |  4   |  5   |  6   |  7   |   8   |   9   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  off|  off |  off |  off |  off |  off |  off |  off |  off |  off  |  off  ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||                                  Thursday                                   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  0  |  1   | 10   |  2   |  3   |  4   |  5   |  6   |  7   |   8   |   9   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  on |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on   |  on   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||                                   Tuesday                                   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  0  |  1   | 10   |  2   |  3   |  4   |  5   |  6   |  7   |   8   |   9   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  on |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on   |  on   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||                                  Wednesday                                  ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  0  |  1   | 10   |  2   |  3   |  4   |  5   |  6   |  7   |   8   |   9   ||||
|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||
||||  on |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on  |  on   |  on   ||||

|||+-----+------+------+------+------+------+------+------+------+-------+-------+|||

http://docs.aws.amazon.com/cli/latest/reference/opsworks/set-time-based-auto-scaling.html

Puppet FAQ

Puppet FAQ

So you have setup your Puppet master and got few servers joined the show. Everything runs smooth and another happy man.

Wait, on the last node, when you almost done with the project, there is one node keep throwing this error

[root@ clinet]# puppet agent --test

err: Could not request certificate: Connection timed out - connect(2)

Exiting; failed to retrieve certificate and waitforcert is disabled

You very certain that you have open all the ports, other nodes talk to master, only this node. Restarting master and client 654 times but no luck.

After spending 2 hours Googling, no luck still.

Out of sudden, you realised that you have not defined puppet master server on node's puppet.conf file
[main]
    # The Puppet log directory.
    # The default value is '$vardir/log'.
    logdir = /var/log/puppet

    # Where Puppet PID files are kept.
    # The default value is '$vardir/run'.
    rundir = /var/run/puppet

    # Where SSL certificates are kept.
    # The default value is '$confdir/ssl'.
    ssldir = $vardir/ssl
    server  = puppetmaster.local 

Hope this post could save someone 120mins, repeating the same I went through.