ec2-filter

A command-line utility to discover EC2 instances and output information like their private IP address, DNS name, etc.

Inspired by aws ec2 describe-instances --filters but easier to deploy and use for service discovery in scripts.

Installation

If you're on Mac OS X, the easiest way to install ec2-filter is via Homebrew:

brew tap mlafeldt/formulas
brew install ec2-filter

For server deployments, the best way to get ec2-filter is to download one of the pre-built binaries from the Releases page.

Alternatively, you can build the tool from source, provided you have Go installed:

go get -u github.com/Jimdo/ec2-filter

Usage

# Export AWS credentials and region
export AWS_ACCESS_KEY_ID=...
export AWS_SECRET_ACCESS_KEY=...
export AWS_REGION=...

# Show private IPs of all running instances
ec2-filter

# Show private DNS names of all running instances
ec2-filter -private-dns

# Show private IPs of all running instances where tag "foo" is set to "bar"
ec2-filter tag:foo=bar

# Concatenate results using space instead of newline
ec2-filter -join " "

# Limit the number of results, e.g. to only get a single IP
ec2-filter -limit 1

# Use custom format string to print additional information, e.g. service port
ec2-filter -format '{{.PrivateIpAddress}}:80'

# Combine the presented features
ec2-filter -format '{{.PrivateIpAddress}}:80' -join " " tag:foo=bar

Invoke ec2-filter -h for a list of all available options.

Examples from our codebase

Run a command on all EC2 instances that are part of our Crims cluster:

pssh -H "$(ec2-filter -join " " tag:jimdo:cluster=crims)" ...

Find the endpoint of one Nomad server:

export NOMAD_ADDR=$(ec2-filter -limit 1 -format 'http://{{.PrivateIpAddress}}:4646' tag:jimdo:cluster=nomad-server)
nomad node-status