KnuckleCluster
Have you ever wanted to shuck away the hard, rough exterior of an ECS cluster and get to the soft, chewy innards? Sounds like you need KnuckleCluster! This tool provides scripts, invoked via cli or rakefile, to list, connect to and/or run commands on ecs agents and containers via ssh. This makes it very easy to interrogate ECS agents and containers without having to go digging for IP addresses and things. Primarily created as a tool to connect to instances in an ECS cluster and see what is running on them, it has evolved slightly to include the ability to list instances in spot requests and auto-scaling groups.
Features
- See what agents in your ECS cluster are doing
- Easily connect to running agents
- Easily connect and get a console inside running containers
- Create shortcuts to oft-used commands and run them easily
- Optionally integrates with aws-vault for AWS authentication
Development Status
Is being used in production for various projects and is considered stable. Any new features/bug fixes etc are most welcome!
Installation
KnuckleCluster can be used in two ways:
- As a system-wide executable with a config file (preferred)
- As a rake task in your project
Install the executable with:
$ gem install knuckle_cluster
OR
Add this line to your application's Gemfile:
source 'https://rubygems.envato.com/' do
gem 'knuckle_cluster'
end
And then execute:
$ bundle
Usage
Knuckle Cluster can be used either as a part of an application via a rakefile, or at a system level.
You'll need to execute knuckle_cluster with appropriate AWS permissions on the cluster in question, stored in your ENV. I like to use aws-vault
to handle this for me.
System usage
Create a file: ~/.ssh/knuckle_cluster
. This is the config file that will be used to make connections from the command line. It is a yaml file. The connection name is the key, and all parameters are below it. EG:
platform:
cluster_name: platform-ecs-cluster-ABC123
region: us-east-1
bastion: platform_bastion
rsa_key_location: ~/.ssh/platform_rsa_key
ssh_username: ubuntu
sudo: true
aws_vault_profile: platform_super_user
shortcuts:
console:
container: web
command: bundle exec rails console
db:
container: worker
command: script/db_console
tunnels:
db:
local_port: 54321
remote_host: postgres-db.yourcompany.com
remote_port: 5432
hide:
container: some_container_regex_i_dont_care_about
task: some_task_regex_i_dont_care_about
You can also use inheritance to simplify the inclusion of multiple similar targets:
super_platform:
<<: *default_platform
cluster_name: super-platform-ecs-cluster-ABC123
ultra_platform:
<<: *default_platform
cluster_name: ultra-platform-ecs-cluster-DEF987
sudo: false
default_platform: &default_platform
region: us-east-1
bastion: platform_bastion
rsa_key_location: ~/.ssh/platform_rsa_key
ssh_username: ubuntu
sudo: true
aws_vault_profile: platform_super_user
other_platform: &other_platform
region: us-east-1
bastion:
username: ubuntu
host: bastion.endpoint.example.com
rsa_key_location: ~/.ssh/bastion_rsa_key
rsa_key_location: ~/.ssh/platform_rsa_key
ssh_username: ubuntu
sudo: true
aws_vault_profile: platform_super_user
See Options for Knuckle Cluster below for a list of what each option does.
Command line options:
knuckle_cluster list - list all available clusters
knuckle_cluster CLUSTER_PROFILE agents - list all agents and select one to start a shell
knuckle_cluster CLUSTER_PROFILE containers - list all containers and select one to start a shell
knuckle_cluster CLUSTER_PROFILE logs CONTAINER_NAME - tail the logs for a container
knuckle_cluster CLUSTER_PROFILE CONTAINER_NAME [OPTIONAL COMMANDS] - connect to a container and start a shell or run a command
knuckle_cluster CLUSTER_PROFILE SHORTCUT_NAME - run a shortcut defined in your knuckle_cluster configuration
knuckle_cluster CLUSTER_PROFILE tunnel TUNNEL_NAME - open a tunnel defined in your knuckle_cluster configuration
knuckle_cluster CLUSTER_PROFILE scp source destination - copied a file via scp to or from a container or agent. Use container:<location> or agent:<location>
Rakefile usage
It takes one argument at minimum: cluster_name
. A region is likely also required as it will default to us-east-1
.
Eg:
kc = KnuckleCluster.new(
cluster_name: 'platform-ecs-cluster-ABC123',
region: 'us-east-1',
bastion: 'platform_bastion',
rsa_key_location: "~/.ssh/platform_rsa_key",
ssh_username: "ubuntu",
sudo: true
)
task :agents do
kc.connect_to_agents
end
task :containers do
kc.connect_to_containers
end
invoke with rake agents
or rake containers
Once you have an instance of KnuckleCluster, you can now do things!
$ knuckle_cluster super_platform containers
Which will give you the output and run bash for you on the actual docker container:
Listing Containers
TASK | AGENT | INDEX | CONTAINER
------------------|---------------------|-------|--------------------
task-one | i-123abc123abc123ab | 1 | t1-container-one
task-two | i-123abc123abc123ab | 2 | t2-container-one
| | 3 | t2-container-two
task-three | i-456def456def456de | 4 | t3-container-one
| | 5 | t3-container-two
| | 6 | t3-container-three
Connect to which container?
Same with connecting directly to agents
$ knuckle_cluster super_platform agents
Listing Agents
INDEX | INSTANCE_ID | TASK | CONTAINER
------|---------------------|------------|--------------------
1 | i-123abc123abc123ab | task-one | t1-container-one
| | task-two | t2-container-one
| | | t2-container-two
2 | i-456def456def456de | task-three | t3-container-one
| | | t3-container-two
| | | t3-container-three
Connect to which agent?
Both connect_to_containers
and connect_to_agents
can have the following optional arguments:
Argument | Description |
---|---|
command | Runs a command on the specified container/agent. When connecting to containers, this defaults to bash
|
auto | Automatically connects to the first container/agent it can find. Handy when used in conjunction with command . |
Eg: To connect to a container, echo something and then immediately disconnect you could use:
kc.connect_to_containers(auto: true, command: "echo I love KnuckleCluster!")
Options for Knuckle Cluster
Possible options are below. If left blank, they will be ignored and defaults used where available.:
Argument | Description |
---|---|
cluster_name | The name of the cluster (not the ARN). eg 'my-super-cluster'. One of cluster_name ,spot_request_id or asg_name is required. |
spot_request_id | The spot request ID you are connecting to. eg 'sfr-abcdef'. One of cluster_name ,spot_request_id or asg_name is required. |
asg_name | The auto-scaling group name you are connecting to. eg 'very-scaly-group'. One of cluster_name ,spot_request_id or asg_name is required. |
region | The AWS region you would like to use. Defaults to us-east-1
|
bastion | if you have a bastion to proxy to your ecs cluster via ssh, put the name of it here as defined in your ~/.ssh/config file. Alternatively, this can be a collection of keys for username , host , and rsa_key_location
|
rsa_key_location | The RSA key needed to connect to an ecs agent eg ~/.ssh/id_rsa . |
ssh_username | The username to conncet. Will default to ec2-user
|
sudo | true or false - will sudo the docker command on the target machine. Usually not needed unless the user is not a part of the docker group. |
aws_vault_profile | If you use the aws-vault tool to manage your AWS credentials, you can specify a profile here that will be automatically used to connect to this cluster. |
profile | Another profile to inherit settings from. Settings from lower profiles can be overridden in higher ones. |
hide | allows you to specify a regex for either task or container to omit these from being shown |
FAQ
Ruby 3 related issue:
ERROR: There was a problem loading your configuration: Alias parsing was not enabled. To enable it, pass `aliases: true` to `Psych::load` or `Psych::safe_load`.
This is an issue with Psych changing the default behaviour around expanding aliases in Ruby 3. See this issue for a workaround.
Spot Fleets
If you wish to see what instances are running within a spot fleet, KnuckleCluster can do that too!. In your config, use spot_request_id
instead of cluster_name
. Note that the containers
command will not work when invoking (use agents
instead).
AutoScaling Groups
If you wish to see what instances are running within an ASG, KnuckleCluster can do that too!. In your config, use asg_name
instead of cluster_name
. Note that the containers
command will not work when invoking (use agents
instead).
SCP
You can use Knuckle Cluster to copy files in and out of agents or containers. Note that this will only work where one of the source or destination is your local machine, copying between containers is not yet supported. Use a syntax similar to existing scp
syntax when specifying a source or destination, but use the keyword container
or agent
for the remote. When using one of these keywords, you will be prompted as to which agent/container you wish to use.
#Copy some_file.txt into a container at /app/some_file.txt
knuckle_cluster super_platform scp ./some_file.txt container:/app/some_file.txt
#Copy /app/some_file.txt from a remote container to ./some_file.txt on your local machine
knuckle_cluster super_platform scp container:/app/some_file.txt ./some_file.txt
#Copy some_file.txt into an agent at ~/some_file.txt
knuckle_cluster super_platform scp ./some_file.txt agent:~/some_file.txt
#Copy /app/some_file.txt from a remote container to ./some_file.txt on your local machine
knuckle_cluster super_platform scp agent:~/some_file.txt ./some_file.txt
Maintainer
Contributors
License
KnuckleCluster
uses MIT license. See
LICENSE.txt
for
details.
Code of conduct
We welcome contribution from everyone. Read more about it in
CODE_OF_CONDUCT.md
Contributing
For bug fixes, documentation changes, and small features:
- Fork it ( https://github.com/[my-github-username]/knuckle_cluster/fork )
- Create your feature branch (git checkout -b my-new-feature)
- Commit your changes (git commit -am 'Add some feature')
- Push to the branch (git push origin my-new-feature)
- Create a new Pull Request
For larger new features: Do everything as above, but first also make contact with the project maintainers to be sure your change fits with the project direction and you won't be wasting effort going in the wrong direction.