Mohawk

Mohawk is a metric data storage engine, it's fun, fast, light and easy to use.

Table of contents

• Introduction
• Installation
• Running the server
• Reading and writing data

Source Modules

• REST API (server) source directory
• Command Line Interface (cli) source directory
• Metric Data Storage (storage) source directory
• Alert Rules (alerts) source directory

Introduction

Mohawk is a metric data storage engine that uses a plugin architecture for data storage and a simple REST API as the primary interface.

Mohawk can use different storage plugins for different use cases. Different storage plugins may vary in speed, persistence and scale ability. Mohawk use a subset of Hawkular's REST API inheriting Hawkular's ecosystem of clients and plugins.

Compatibility

Mohawk is tested(1) with Hawkular plugins, like Hawkular Grafana Plugin and clients like Python and Ruby. Mohawk also work with Heapster to automagically scrape metrics from Kubernetes / OpenShift clusters.

Mohawk can also serve as Prometheus scraping endpoint.

(1) Mohawk implement only a subset of Hawkular's API, some functionality may be missing.

Installation

Using a Copr repository for Fedora

sudo dnf copr enable yaacov/mohawk
sudo dnf install mohawk

Using Dockerhub repository

docker run -v [PATH TO KEY AND CERT FILES]:/root/ssh:Z yaacov/mohawk

Building from source

# Create a directory for sources
mkdir -p ${GOPATH}/src/github.com/MohawkTSDB && cd ${GOPATH}/src/github.com/MohawkTSDB

# Clone the sources from the git repository
git clone https://github.com/MohawkTSDB/mohawk.git
cd mohawk

# Update vedor sources
make vendor

# Build, test and install
make clean
make
make test
make install

# Set up tls secrets for testing
make secret

Running the server

The server command line interface

Request usage message.

mohawk -h
Usage of mohawk:
...

mohawk --options=help
Storage options:
...

Running mohawk without tls and using the sqlite back end.

mohawk --storage sqlite
2017/01/03 10:06:50 Start server, listen on http://0.0.0.0:8080

Running the server with tls, gzip encoding support and using the memory storage.

Remember to set up the server.key and server.pem files in your path

mohawk --storage memory --tls --gzip --port 8443
2016/12/01 14:23:48 Start server, listen on https://0.0.0.0:8443

Mock Certifications for testing

The server requires certification to serve https requests. Users can use self signed credentials files for testing.

To create a self signed credentials use this bash commands:

openssl ecparam -genkey -name secp384r1 -out server.key
openssl req -new -x509 -sha256 -key server.key -out server.pem -days 3650

If running from source, the Makefile has a utility for generating secrets:

make secret

Running the server for this examples

Using TLS server requires certification files, default file names are server.key and server.pem .

mohawk --tls --gzip --port 8443

Reading and writing data

Common queries

# get server status
curl -ks https://localhost:8443/hawkular/metrics/status

# get a list of all metrics
curl -ks https://localhost:8443/hawkular/metrics/metrics

# post some data (timestamp is in ms)
curl -ks -X POST https://localhost:8443/hawkular/metrics/gauges/raw \
     -d "[{\"id\":\"machine/example.com/test\", \"data\":[{\"timestamp\": 1492434911769, \"value\": 42}]}]"

# read some data (variables can be start, end and bucketDuration)
curl -ks https://localhost:8443/hawkular/metrics/gauges/machine%2Fexample.com%2Ftest/raw?start=1492434911760

Tags

# set tags
curl -ks -X PUT https://localhost:8443/hawkular/metrics/gauges/tags \
     -d "[{\"id\":\"machine/example.com/test\",\"tags\":{\"type\":\"node\",\"hostname\":\"example.com\"}}]"

# look for metrics by tag value (using a regexp)
curl -ks https://localhost:8443/hawkular/metrics/metrics?tags=hostname:.*\.com

Search

# read multiple data points using an ids list
curl -ks -X POST https://localhost:8443/hawkular/metrics/gauges/raw/query \
     -d "{\"ids\": [\"machine/example.com/test\"], \"start\": 1492434811769, \"end\": 1492435911769}"

# read multiple data points using a regexp search on tags
curl -ks -X POST https://localhost:8443/hawkular/metrics/gauges/raw/query \
     -d "{\"tags\": \"name:.*test|.*machine\", \"start\": \"-12h\"}"

Aggregation

# using relative start time, and aggregation time of 2mn
curl -ks -X POST https://localhost:8443/hawkular/metrics/gauges/raw/query \
     -d "{\"ids\": [\"machine/example.com/test\"], \"start\":  \"-6h\", \"bucketDuration\": \"2mn\"}"

Data encoding, using gzip data encoding

# using the zcat utility to decode gzip message
curl -ks -H "Accept-Encoding: gzip" https://localhost:8443/hawkular/metrics/metrics | zcat

# sendig gziped data file with curl's --data-binary flag
curl -ks -H "Content-Encoding: gzip" -X PUT "https://localhost:8443/hawkular/metrics/gauges/tags" \
     --data-binary @tags.json.gz

Issues? Questions?

Github Project / Mohawk TSDB