Overcast is a simple terminal-based cloud management tool that was designed to make it easy to spin up and manage clusters of servers in a consistent, scriptable way. Inspired by Packer.io.
Define clusters and instances using the command line or by editing a simple JSON file.
$ overcast cluster create db
$ overcast cluster create app
$ overcast instance import app.01 --cluster app --ip 127.0.0.2 \
--ssh-port 22222 --ssh-key $HOME/.ssh/id_rsa
$ overcast instance import app.02 --cluster app --ip 127.0.0.3 \
--ssh-port 22222 --ssh-key $HOME/.ssh/id_rsa
Create, snapshot and destroy instances on DigitalOcean (EC2/Linode support is on the roadmap).
# Create a new Ubuntu 12.04 instance:
$ overcast digitalocean create db.01 --cluster db
# Configure the instance to your liking:
$ overcast run db.01 install/core install/redis
$ overcast expose db.01 22 6379
# Create a snapshot:
$ overcast digitalocean snapshot db.01 my.db.snapshot
# Spin up a cluster using your snapshot:
$ overcast digitalocean create db.02 --cluster db --image-name my.db.snapshot
$ overcast digitalocean create db.03 --cluster db --image-name my.db.snapshot
$ overcast digitalocean create db.04 --cluster db --image-name my.db.snapshot
Run commands or script files across any number of servers. Commands can be run sequentially or in parallel.
$ overcast run db install/core install/redis
$ overcast run all uptime "free-m" "df -h" --parallel
Push and pull files between your local machine and an instance, a cluster, or all clusters. Dynamically rewrite file paths to include the instance name.
$ overcast push app nginx/myapp.conf /etc/nginx/sites-enabled/myapp.conf
$ overcast pull all /etc/nginx/sites-enabled/myapp.conf nginx/{instance}.myapp.conf
Overcast is a thin wrapper around your native SSH client, and doesn't install or leave anything on the servers you communicate with.
A script library is included to make it easy to install common software components. The library was written for Ubuntu servers, but could be extended to include other distributions.
Install Node.js if not already installed.
Install Overcast using npm.
$ npm -g install overcast
You can now use Overcast from any directory.
$ overcast help
Overcast looks for an .overcast directory in the current directory, or in some parent directory, otherwise falling back to $HOME/.overcast. This allows you to have multiple configurations, and to check your cluster definitions and scripts into a repo, like source code.
The command overcast init will create a new configuration in the current directory. The config directory looks like this:
.overcast
/files # Files to be copied to instances
/keys # SSH keys. Can be your own or auto-generated by overcast
/scripts # Scripts to be run on instances
/clusters.json # Cluster/instance definitions (see example.clusters.json)
/variables.json # API keys, etc (see example.variables.json)
overcast cluster count [name]
Return the number of instances in a cluster.
Example:
$ overcast cluster count db
> 0
$ overcast instance create db.01 --cluster db
> ...
$ overcast cluster count db
> 1
overcast cluster create [name]
Creates a new cluster.
Example:
$ overcast cluster create db
overcast cluster rename [name] [new-name]
Renames a cluster.
Example:
$ overcast cluster rename app-cluster app-cluster-renamed
overcast cluster remove [name]
Removes a cluster from the index. If the cluster has any instances
attached to it, they will be moved to the "orphaned" cluster.
Example:
$ overcast cluster remove db
overcast completions
Return an array of commands, cluster names, and instance names for use
in bash tab completion.
To enable tab completion in bash, add this to your .bash_profile:
_overcast_completions() {
local cur=${COMP_WORDS[COMP_CWORD]}
COMPREPLY=($(compgen -W "`overcast completions`" -- "$cur"))
return 0
}
complete -F _overcast_completions overcast
These functions require the following values set in .overcast/variables.json:
DIGITALOCEAN_CLIENT_ID
DIGITALOCEAN_API_KEY
overcast digitalocean create [name] [options]
Creates a new instance on DigitalOcean.
The instance will start out using the auto-generated SSH key found here:
/path/to/.overcast/keys/overcast.key.pub
You can specify region, image, and size of the droplet using -id or -slug.
You can also specify an image or snapshot using --image-name.
Option | Default
--cluster CLUSTER |
--ssh-port PORT | 22
--region-slug NAME | nyc2
--region-id ID |
--image-slug NAME | ubuntu-12-04-x64
--image-id ID |
--image-name NAME |
--size-slug NAME | 512mb
--size-id ID |
Example:
$ overcast instance create db.01 --cluster db --size-slug 1gb --region-slug sfo1
overcast digitalocean destroy [instance]
Destroys a DigitalOcean droplet and removes it from your account.
Using --force overrides the confirm dialog. This is irreversible.
Option | Default
--force | false
Example:
$ overcast digitalocean destroy app.01
overcast digitalocean droplets
List all DigitalOcean droplets in your account.
overcast digitalocean images
List all available DigitalOcean images. Includes snapshots.
overcast digitalocean poweron [instance]
Power on a powered off droplet.
overcast digitalocean reboot [instance]
Reboots a DigitalOcean droplet. According to the API docs, "this is the
preferred method to use if a server is not responding."
Example:
$ overcast digitalocean reboot app.01
overcast digitalocean rebuild [instance] [options]
Rebuild a DigitalOcean droplet using a specified image name, slug or ID.
According to the API docs, "This is useful if you want to start again but
retain the same IP address for your droplet."
Option | Default
--image-slug SLUG | ubuntu-12-04-x64
--image-name NAME |
--image-id ID |
Example:
$ overcast digitalocean rebuild app.01 --name my.app.snapshot
overcast digitalocean regions
List available DigitalOcean regions (nyc2, sfo1, etc).
overcast digitalocean resize [name] [options]
Shutdown, resize, and reboot a DigitalOcean droplet.
If --skipboot flag is used, the droplet will stay in a powered-off state.
Option | Default
--size-slug NAME |
--size-id ID |
--skipBoot | false
Example:
$ overcast instance resize db.01 --size-slug 2gb
overcast digitalocean sizes
List available DigitalOcean sizes (512mb, 1gb, etc).
overcast digitalocean shutdown [instance]
Shut down a DigitalOcean droplet.
Example:
$ overcast digitalocean shutdown app.01
overcast digitalocean snapshot [instance] [snapshot-name]
Creates a named snapshot of a droplet. This process will reboot the instance.
Example:
$ overcast digitalocean snapshot app.01
overcast digitalocean snapshots
Lists available snapshots in your DigitalOcean account.
overcast expose [instance|cluster|all] [port...]
Reset the exposed ports on the instance or cluster using iptables.
This will fail if you don't include the current SSH port.
Specifying --whitelist will restrict all ports to the specified address(es).
These can be individual IPs or CIDR ranges, such as "192.168.0.0/24".
Expects an Ubuntu server, untested on other distributions.
Option
--user=NAME
--whitelist "IP|RANGE..."
--whitelist-PORT "IP|RANGE..."
Examples:
# Allow SSH, HTTP and HTTPS connections from anywhere:
$ overcast expose app 22 80 443
# Allow SSH from anywhere, only allow Redis connections from 1.2.3.4:
$ overcast expose redis 22 6379 --whitelist-6379 "1.2.3.4"
# Only allow SSH and MySQL connections from 1.2.3.4 or from 5.6.7.xxx:
$ overcast expose mysql 22 3306 --whitelist "1.2.3.4 5.6.7.0/24"
overcast exposed [instance|cluster|all]
List the exposed ports on the instance or cluster.
Expects an Ubuntu server, untested on other distributions.
Option | Default
--user NAME |
overcast health [instance|cluster|all]
Export common health statistics in JSON format.
Expects an Ubuntu server, untested on other distributions.
Example JSON:
{
"my_instance_name": {
"cpu_1min": 0.53,
"cpu_5min": 0.05,
"cpu_15min": 0.10,
"disk_total": 19592, // in MB
"disk_used": 13445, // in MB
"disk_free": 5339, // in MB
"mem_total": 1000, // in MB
"mem_used": 904, // in MB
"mem_free": 96, // in MB
"cache_used": 589, // in MB
"cache_free": 410, // in MB
"swap_total": 255, // in MB
"swap_used": 124, // in MB
"swap_free": 131, // in MB
"tcp": 152, // open TCP connections
"rx_bytes": 196396703, // total bytes received
"tx_bytes": 47183785, // total bytes transmitted
"io_reads": 1871210, // total bytes read
"io_writes": 6446448, // total bytes written
"processes": [
{
"user": "root",
"pid": 1,
"cpu%": 0,
"mem%": 0,
"time": "0:01",
"command": "/sbin/init"
}
]
}
}
Overcast v0.1.29
Code repo, issues, pull requests:
https://github.com/andrewchilds/overcast
Usage:
overcast [command] [options...]
Help:
overcast help
overcast help [command]
overcast [command] help
Commands:
overcast cluster list
overcast cluster count [name]
overcast cluster create [name]
overcast cluster rename [name] [new-name]
overcast cluster remove [name]
overcast completions
overcast digitalocean create [instance] [options]
overcast digitalocean destroy [instance]
overcast digitalocean droplets
overcast digitalocean images
overcast digitalocean poweron [instance]
overcast digitalocean reboot [instance]
overcast digitalocean rebuild [instance] [options]
overcast digitalocean regions
overcast digitalocean resize
overcast digitalocean sizes
overcast digitalocean shutdown [instance]
overcast digitalocean snapshot [instance] [snapshot-name]
overcast digitalocean snapshots
overcast expose [instance|cluster|all] [port...] [options]
overcast exposed [instance|cluster|all]
overcast health [instance|cluster|all]
overcast info
overcast init
overcast instance get [name] [attr...]
overcast instance import [name] [options]
overcast instance list [cluster...]
overcast instance remove [name]
overcast instance update [name] [options]
overcast list
overcast ping [instance|cluster|all]
overcast port [instance|cluster|all] [port]
overcast pull [instance|cluster|all] [source] [dest]
overcast push [instance|cluster|all] [source] [dest]
overcast run [instance|cluster|all] [command...]
overcast run [instance|cluster|all] [file...]
overcast ssh [instance]
Config directory:
/path/to/.overcast
overcast info
Pretty-prints the complete clusters.json file, stored here:
/path/to/.overcast/clusters.json
overcast init
Create an .overcast config directory in the current working directory.
No action taken if one already exists.
overcast instance get [name] [attr...]
Returns the instance attribute(s), one per line.
Examples:
$ overcast instance get app.01 ssh-port ip
> 22
> 127.0.0.1
$ overcast instance get app.01 user
> appuser
overcast instance import [name] [options]
Imports an existing instance to a cluster.
Option | Default
--cluster CLUSTER |
--ip IP |
--ssh-port PORT | 22
--ssh-key PATH | .overcast/keys/overcast.key
--user USERNAME | root
Example:
$ overcast instance import app.01 --cluster app --ip 127.0.0.1 \
--ssh-port 22222 --ssh-key $HOME/.ssh/id_rsa
overcast instance list [cluster...]
Returns all instance names, one per line. Optionally limit to one or more clusters.
Examples:
$ overcast instance list
$ overcast instance list app-cluster db-cluster
overcast instance remove [name]
Removes an instance from the index.
The server itself is not affected by this action.
Example:
$ overcast instance remove app.01
overcast instance update [name] [options]
Update any instance property. Specifying --cluster will move the instance to
that cluster. Specifying --name will rename the instance.
Option | Default
--name NAME |
--cluster CLUSTER |
--ip IP |
--ssh-port PORT |
--ssh-key PATH |
--user USERNAME |
Example:
$ overcast instance update app.01 --user differentuser --ssh-key /path/to/another/key
overcast list
Short list of your cluster and instance definitions, stored here:
/path/to/.overcast/clusters.json
overcast ping [instance|cluster|all]
Ping an instance or cluster.
Option | Default
--count N | 3
Examples:
$ overcast ping app.01
$ overcast ping db --count 5
overcast port [instance|cluster|all] [port]
Change the SSH port for an instance or a cluster.
This command will fail if the new port is not opened by iptables.
Examples:
$ overcast port app.01 22222
$ overcast port db 22222
overcast pull [instance|cluster|all] [source] [dest]
Pull a file or directory from an instance or cluster using scp. Source is absolute.
Destination can be absolute or relative to the .overcast/files directory.
Any reference to {instance} in the destination will be replaced with the instance name.
Option
--user NAME
Example:
Assuming instances "app.01" and "app.02", this will expand to:
- .overcast/files/nginx/app.01.myapp.conf
- .overcast/files/nginx/app.02.myapp.conf
$ overcast pull app /etc/nginx/sites-enabled/myapp.conf nginx/{instance}.myapp.conf
overcast push [instance|cluster|all] [source] [dest]
Push a file or directory to an instance or cluster using scp. Source can be
absolute, or relative to the .overcast/files directory. Destination is absolute.
Any reference to {instance} in the source will be replaced with the instance name.
Option
--user NAME
Example:
Assuming instances "app.01" and "app.02", this will expand to:
- .overcast/files/nginx/app.01.myapp.conf
- .overcast/files/nginx/app.02.myapp.conf
$ overcast push app nginx/{instance}.myapp.conf /etc/nginx/sites-enabled/myapp.conf
overcast run [instance|cluster|all] [command...]
Runs a command or series of commands on an instance or cluster.
Commands will run sequentially unless you use the --parallel flag,
in which case each command will run on all instances simultanously.
Option | Default
--env "KEY=VAL KEY='1 2 3'" |
--user NAME |
--ssh-key PATH |
--parallel -p | false
--continueOnError | false
Examples:
$ overcast run app --env "foo='bar bar' testing=123" env
$ overcast run all uptime "free -m" "df -h"
overcast run [instance|cluster|all] [file...]
Executes a script file or files on an instance or cluster.
Script files can be either absolute or relative path.
Script files will run sequentially unless you use the --parallel flag,
in which case each file will execute on all instances simultanously.
Option | Default
--env "KEY=VAL KEY='1 2 3'" |
--user NAME |
--ssh-key PATH |
--shell-command "COMMAND" | bash -s
--parallel -p | false
--continueOnError | false
Relative paths are relative to the cwd, or to these directories:
/path/to/.overcast/scripts
/path/to/installed/overcast/.overcast/scripts
Example:
$ overcast run db install/core install/redis
overcast ssh [instance]
Opens an SSH connection to an instance.
Option
--ssh-key PATH
--user NAME
There are a lot of server management frameworks out there already (Chef, Puppet, Ansible, Salt), but they all involve either a complex server-client implementation, a steep learning curve or a giant, monolithic conceptual framework that requires taking a course to understand.
I wanted something that had little to no learning curve, that just focused on multi-server provisioning and communication and leaves problems like process/state management and system monitoring to tools designed specifically for those problems (Monit, Munin, Nagios, etc).
npm install
npm test
npm -g update overcast
Configuration files are left alone during an upgrade.
Contributions are very welcome. If you've got an idea for a feature or found a bug, please open an issue. If you're a developer and want to help make Overcast better, open a pull request with your changes.
MIT. Copyright © 2014 Andrew Childs.
FAQs
A simple command line program that makes it easy to spin up, configure, and manage virtual machines over SSH.
The npm package overcast receives a total of 23 weekly downloads. As such, overcast popularity was classified as not popular.
We found that overcast demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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