LSI

The lsi command provides an easy way to rapidly query AWS to find information about an instance, SSH onto it, or run an SSH command on multiple hosts in parallel.

Instance search

Searching for an instance is exceedingly easy. Simply type lsi followed by zero or more filters, which are substrings of an instance's name, IP address, or other identifying information:

> lsi stg database
+---------------------------------------|-----------+
| Instance Name                         | Public IP |
| database-data-stg-1                   | 10.0.1.2  |
| database-data-stg-2                   | 10.0.1.2  |
| database-data-stg-3                   | 10.0.1.2  |
| database-services-stg-1               | 10.0.1.2  |
| database-services-stg-2               | 10.0.1.2  |
| database-services-stg-3               | 10.0.1.2  |
| stg-database-config-server-i-153dc5e9 | 10.0.1.2  |
| stg-database-config-server-i-1d21dcf5 | 10.0.1.2  |
| stg-database-config-server-i-2bd0d1c5 | 10.0.1.2  |
+---------------------------------------|-----------+

You can provide exclusionary filters with -v:

> lsi stg database -v services
+---------------------------------------|-----------+
| Instance Name                         | Public IP |
| database-rs-data-stg-1                | 10.0.1.2  |
| database-rs-data-stg-2                | 10.0.1.2  |
| database-rs-data-stg-3                | 10.0.1.2  |
| stg-database-config-server-i-153dc5e9 | 10.0.1.2  |
| stg-database-config-server-i-1d21dcf5 | 10.0.1.2  |
| stg-database-config-server-i-2bd0d1c5 | 10.0.1.2  |
+---------------------------------------|-----------+

The table by default will consist only of machine names and public IPs. You can pull up additional information by passing the --show argument:

> lsi stg database --show private_ip
+---------------------------------------|-----------|------------+
| Instance Name                         | Public IP | Private IP |
| database-rs-data-stg-1                | 10.0.1.2  | 10.0.1.2   |
| database-rs-data-stg-2                | 10.0.1.2  | 10.0.1.2   |
| database-rs-data-stg-3                | 10.0.1.2  | 10.0.1.2   |
| database-rs-services-stg-1            | 10.0.1.2  | 10.0.1.2   |
| database-rs-services-stg-2            | 10.0.1.2  | 10.0.1.2   |
| database-rs-services-stg-3            | 10.0.1.2  | 10.0.1.2   |
| stg-database-config-server-i-153dc5e9 | 10.0.1.2  | 10.0.1.2   |
| stg-database-config-server-i-1d21dcf5 | 10.0.1.2  | 10.0.1.2   |
| stg-database-config-server-i-2bd0d1c5 | 10.0.1.2  | 10.0.1.2   |
+---------------------------------------|-----------|------------+

You can see all of the things that are available to show by requesting --attributes:

> lsi --attributes
The following attributes are available: logical_id, ami_id, name, tags, stack_name, hostname, launch_time, public_ip, instance_type, private_ip, stack_id, security_groups

SSH onto an instance

Often the reason for searching in the first place is to SSH onto one of the instances you find. Rather than copy/pasting manually, you can do this directly from lsi using the --ssh or -s flag:

> lsi -s stg database data
+---|---------------------|-------------------------------------------|---------------+
|   | Instance Name       | Hostname                                  | Public IP     |
| 0 | database-data-stg-1 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
| 1 | database-data-stg-2 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
| 2 | database-data-stg-3 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
+---|---------------------|-------------------------------------------|---------------+
3 matching entries.
Commands:
  <n>: Connect to the nth instance in the list
  u username: Change SSH username to username (currently none set)
  i idfile: Change identity file to idfile (currently none set)
  f <one or more patterns>: Restrict results to those with patterns
  e <one or more patterns>: Restrict results to those without patterns
  c <command>: Set ssh command to run on matching hosts (currently none set)
  x: Execute the above command on the above host(s)
  q: Quit
Enter command:

At this point, you can enter the number of the instance you want to SSH onto, which will immediately SSH you onto a machine.

Of course, you might not have permissions onto a machine with your own username, or you might want to log in as another user or with a specific identity file. You can do this with --username (-u) and --identity-file (-i), respectively. If you do this, you don't need to pass the -s flag.

> lsi -u someuser -i ~/.ssh/somekey.pem stg database data
+---|---------------------|-------------------------------------------|---------------+
|   | Instance Name       | Hostname                                  | Public IP     |
| 0 | database-data-stg-1 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
| 1 | database-data-stg-2 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
| 2 | database-data-stg-3 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
+---|---------------------|-------------------------------------------|---------------+
3 matching entries.
Commands:
  <n>: Connect to the nth instance in the list
  u username: Change SSH username to username (currently someuser)
  i idfile: Change identity file to idfile (currently /home/anelson/.ssh/somekey.pem)
  f <one or more patterns>: Restrict results to those with patterns
  e <one or more patterns>: Restrict results to those without patterns
  c <command>: Set ssh command to run on matching hosts (currently none set)
  x: Execute the above command on the above host(s)
  q: Quit
Enter command:

Running SSH commands across instances

You can use lsi to execute an SSH command remotely on one or more instances. To do this, use the --command (-c) option. Enter x at the confirmation screen.

> lsi -c hostname stg database data
+---|---------------------|-------------------------------------------|---------------+
|   | Instance Name       | Hostname                                  | Public IP     |
| 0 | database-data-stg-1 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
| 1 | database-data-stg-2 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
| 2 | database-data-stg-3 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
+---|---------------------|-------------------------------------------|---------------+
3 matching entries.
Commands:
  <n>: Connect to the nth instance in the list
  u username: Change SSH username to username (currently none set)
  i idfile: Change identity file to idfile (currently none set)
  f <one or more patterns>: Restrict results to those with patterns
  e <one or more patterns>: Restrict results to those without patterns
  c <command>: Set ssh command to run on matching hosts (currently hostname)
  x: Execute the above command on the above host(s)
  q: Quit
Enter command: x
Running command `hostname` on 3 matching hosts
[database-data-stg-2 (10.0.1.2)]: ip-10.0.1.2
[database-data-stg-3 (10.0.1.2)]: ip-10.0.1.2
[database-data-stg-1 (10.0.1.2)]: ip-10.0.1.2
All commands finished

Profiles

It can be a bit tedious to enter extensive command-line arguments, especially if they are the same over and over again. To alleviate this, you can create profiles for LSI, which are collections of configuration. For example, you can create a someuser profile which uses the someuser username and appropriate keyfile. To do this, add a section to .lsi, which is written in the ini format. For example:

[someuser]
username=someuser
identity file=~/.ssh/somekey.pem

You can then invoke your profile with --profile (-p):

> lsi -p someuser stg database data
+---|---------------------|-------------------------------------------|---------------+
|   | Instance Name       | Hostname                                  | Public IP     |
| 0 | database-data-stg-1 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
| 1 | database-data-stg-2 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
| 2 | database-data-stg-3 | ec2-W-X-Y-Z.compute-1.amazonaws.com       | 10.0.1.2      |
+---|---------------------|-------------------------------------------|---------------+
3 matching entries.
Commands:
  <n>: Connect to the nth instance in the list
  u username: Change SSH username to username (currently someuser)
  i idfile: Change identity file to idfile (currently /home/anelson/.ssh/somekey.pem)
  f <one or more patterns>: Restrict results to those with patterns
  e <one or more patterns>: Restrict results to those without patterns
  c <command>: Set ssh command to run on matching hosts (currently none set)
  x: Execute the above command on the above host(s)
  q: Quit
Enter command:

Profiles can inherit from other profiles, allowing you to avoid repetition. For example, you might put the entire above command into a profile:

[someuser]
username=someuser
identity file=~/.ssh/somekey.pem

[stg-database]
inherits=someuser
filters=stg,database,data

Then the lsi -p stg-database command will be equivalent to the above.

Installation

Via pip:

$ pip install lsi