Redalert

For monitoring your infrastructure and sending notifications if stuff is not ok. (e.g. pinging your websites/APIs via HTTP GET at specified intervals, and alerting you if there is downtime).

Features

Checks

• Website monitoring & latency measurement (check type: web-ping)
• Server metrics from local machine (check type: scollector)
• Docker container metrics (check type: docker-stats)
• Docker container metrics from remote host via SSH (check type: remote-docker)
• Postgres counts/stats via SQL queries (check type: postgres)
• TCP connectivity monitoring & latency measurement (check type: tcp)
• Execute local commands & capture output (check type: command)
• Execute remote commands via SSH & capture output (check type: remote-command)
• Run test suite and capture report metrics via JUnit XML format (check type: test-report)

Checks will happen at specified intervals or explicit trigger (i.e. trigger check API endpoint).

Dashboard and Alerts

• Alert notifications available on several channels:
  • sending email (gmail)
  • sending SMS (twilio)
  • posting a message to Slack (slack)
  • unix stream (stderr)
• Provides ping status & latency info to stdout.
• Adjustable back-off after a check fails (constant, linear, exponential - see notes below).
• Includes a web UI as indicated by the screenshot above. (visit localhost:8888/, configure port via cli flag)
• Triggers a failure alert (redalert) when a check is failing, and a recovery alert (greenalert) when the check has recovered (e.g. a successful ping, following a failing ping).
• Triggers an alert when specified metric is above/below threshold.

Assertions

• Assertions are used to define criteria for checks to pass or fail:
• Assert on metrics
  • source: metric
  • > or greater than
  • >= or greater than or equal
  • < or less than
  • <= or less than or equal
  • == or = or equals
• Assert on metadata
  • source: metadata
  • web-ping returns status_code
• Assert on response
  • source: text
  • source: json

API

Design

         ┌──────────────────────────────┐
         │                              │
   ┌────▶│     Redalert Check Flow      │
   │     │                              │
   │     └──────────────────────────────┘
   │                    │
   │          @interval or ->trigger   ┌──────────────────────┐
   │                    │            ┌▶│  error during check  │
   │                    ▼            │ └──────────────────────┘
   │        ┌──────────────────────┐ │ ┌──────────────────────┐
   │        │  is check failing?   │─┤ │  failing assertions  │
   │        └──────────────────────┘ │ │     * metrics *      │
   │                    │            └▶│     * metadata *     │
   │          ┌───YES───┴───NO────┐    │     * response *     │
   │          │                   │    └──────────────────────┘
   │          ▼                   ▼
   │  ┌───────────────┐   ┌───────────────┐
   │  │send alerts via│   │   is check    │
   │  │   notifiers   │   │  recovering?  │
   │  └───────────────┘   └───────────────┘
   │  ┌───────────────┐          YES
   │  │adjust backoff │           │
   │  └───────────────┘           ▼
   │          │           ┌───────────────┐
   │          │           │send alerts via│
   │          │           │   notifiers   │
   │          │           └───────────────┘
   │          │           ┌───────────────┐
   │          │           │ reset backoff │
   │          │           └───────────────┘
   │          │                   │
   │          ▼                   ▼
   │         ┌──────────────────────┐
   └─────────│    Event Storage     │
             └──────────────────────┘

Screenshots

Getting started

Run via Docker:

docker run -d -P -v /path/to/config.json:/config.json jonog/redalert

Quick bootstrap example:

curl https://gist.githubusercontent.com/jonog/32c953aedf03edf71acaef53d89ce785/raw/e87f7e933165574e1d441781465223bfe6c3f1aa/sample_redalert_config.json > /tmp/sample_redalert_config.json && \
    docker run -d -P -v /tmp/sample_redalert_config.json:/config.json --name test_redalert jonog/redalert && \
    open "http://$(docker port test_redalert 8888)"

Usage

Get started with the redalert command:

Usage:
  redalert [command]

Available Commands:
  checks      List checks
  config-sync Sync file and database configurations
  server      Run checks and server stats
  version     Print the version number of Redalert

Flags:
  -d, --config-db string     config database url
  -f, --config-file string   config file (default "config.json")
  -s, --config-s3 string     config S3
  -u, --config-url string    config url
  -h, --help                 help for redalert
  -p, --port int             port to run web server (default 8888)
  -r, --rpc-port int         port to run RPC server (default 8889)

Use "redalert [command] --help" for more information about a command.

Configuration

Configure servers to monitor & alert settings via a configuration file:

• a local file (specified by -f or --config-file) - defaults to config.json
• a file remotely accessible via HTTP (specified by -u or --config-url)
• a file hosted in an AWS S3 bucket (specified by -s or --config-s3)

TODO: document Postgres configuration option

Example config.json

{
   "checks":[
      {
         "name":"Google",
         "type": "web-ping",
         "config": {
            "address":"http://google.com"
         },
         "send_alerts": ["stderr"],
         "backoff": {
            "type": "constant",
            "interval": 10
         },
         "assertions": [
             {
                 "comparison": "==",
                 "identifier": "status_code",
                 "source": "metadata",
                 "target": "200"
             }
         ]
      }
   ],
   "notifications": []
}

Example Larger config.json

{
    "checks": [
        {
            "name": "Demo HTTP Status Check",
            "type": "web-ping",
            "config": {
                "address": "http://httpstat.us/200",
                "headers": {
                    "X-Api-Key": "ABCD1234"
                }
            },
            "send_alerts": [
                "stderr"
            ],
            "backoff": {
                "interval": 10,
                "type": "constant"
            },
            "assertions": [
                {
                    "comparison": "==",
                    "identifier": "status_code",
                    "source": "metadata",
                    "target": "200"
                }
            ]
        },
        {
            "name": "Demo Response Check",
            "type": "web-ping",
            "config": {
                "address": "http://httpstat.us/400"
            },
            "send_alerts": [
                "stderr",
                "email",
                "chat",
                "sms"
            ],
            "backoff": {
                "interval": 10,
                "type": "linear"
            },
            "assertions": [
                {
                    "comparison": "less than",
                    "identifier": "latency",
                    "source": "metric",
                    "target": "1100"
                },
                {
                    "comparison": "==",
                    "identifier": "status_code",
                    "source": "metadata",
                    "target": "400"
                },
                {
                    "comparison": "==",
                    "source": "text",
                    "target": "400 Bad Request"
                }
            ],
            "verbose_logging": true
        },
        {
            "name": "Demo Exponential Backoff",
            "type": "web-ping",
            "config": {
                "address": "http://httpstat.us/200"
            },
            "send_alerts": [
                "stderr"
            ],
            "backoff": {
                "interval": 10,
                "multiplier": 2,
                "type": "exponential"
            },
            "assertions": [
                {
                    "comparison": "==",
                    "identifier": "status_code",
                    "source": "metadata",
                    "target": "500"
                }
            ]
        },
        {
            "name": "Docker Redis",
            "type": "tcp",
            "config": {
                "host": "192.168.99.100",
                "port": 1001
            },
            "send_alerts": [
                "stderr"
            ],
            "backoff": {
                "interval": 10,
                "type": "constant"
            }
        },
        {
            "name": "Docker stats",
            "type": "docker-stats",
            "config": {},
            "send_alerts": [
                "stderr"
            ],
            "backoff": {
                "interval": 30,
                "type": "linear"
            }
        },
        {
            "name": "production-docker-host",
            "type": "remote-docker",
            "config": {
                "host": "ec2-xx-xxx-xx-xxx.ap-southeast-1.compute.amazonaws.com",
                "user": "ubuntu"
            },
            "send_alerts": [
                "stderr"
            ],
            "backoff": {
                "interval": 5,
                "type": "linear"
            }
        },
        {
            "name": "scollector-metrics",
            "type": "scollector",
            "config": {
                "host": "hostname"
            },
            "send_alerts": [
                "stderr"
            ],
            "backoff": {
                "interval": 15,
                "type": "constant"
            }
        },
        {
            "name": "production-db",
            "type": "postgres",
            "config": {
                "connection_url": "postgres://user:pass@localhost:5432/dbname?sslmode=disable",
                "metric_queries": [
                    {
                        "metric": "client_count",
                        "query": "select count(*) from clients"
                    }
                ]
            },
            "send_alerts": [
                "stderr"
            ],
            "backoff": {
                "interval": 120,
                "type": "linear"
            }
        },
        {
            "name": "README size",
            "type": "command",
            "config": {
                "command": "cat README.md | wc -l",
                "output_type": "number"
            },
            "send_alerts": [
                "stderr"
            ],
            "backoff": {
                "interval": 10,
                "type": "constant"
            }
        },
        {
            "name": "List files",
            "type": "command",
            "config": {
                "command": "ls"
            },
            "send_alerts": [
                "stderr"
            ],
            "backoff": {
                "interval": 10,
                "type": "constant"
            }
        },
        {
            "name": "SHH into docker-alpine-sshd",
            "type": "remote-command",
            "config": {
                "command": "uptime",
                "ssh_auth_options": {
                  "user": "root",
                  "password": "root",
                  "host": "localhost",
                  "port": 2222
                }
            },
            "send_alerts": [
                "stderr"
            ],
            "assertions": [
                {
                    "comparison": "==",
                    "identifier": "exit_status",
                    "source": "metadata",
                    "target": "0"
                }
            ]
        },
        {
            "name": "Run Smoke Tests",
            "type": "test-report",
            "config": {
                "command": "./run-smoke-tests.sh"
            },
            "send_alerts": [
                "stderr"
            ],
            "assertions": [
                {
                    "comparison": "==",
                    "identifier": "status",
                    "source": "metadata",
                    "target": "PASSING"
                }
            ]
        }
    ],
    "notifications": [
        {
            "name": "email",
            "type": "gmail",
            "config": {
                "notification_addresses": "",
                "pass": "",
                "user": ""
            }
        },
        {
            "name": "chat",
            "type": "slack",
            "config": {
                "channel": "#general",
                "icon_emoji": ":rocket:",
                "username": "redalert",
                "webhook_url": ""
            }
        },
        {
            "name": "sms",
            "type": "twilio",
            "config": {
                "account_sid": "",
                "auth_token": "",
                "notification_numbers": "",
                "twilio_number": ""
            }
        }
    ],
    "preferences": {
        "notifications": {
          "fail_count_alert_threshold": 2,
          "repeat_fail_alerts": false
        }
    }
}

Build and run (capture stderr).

go build

./redalert 2> errors.log

Notification Preferences

• fail_count_alert_threshold controls sending an alert, only after N fails (defaults to 1)
• repeat_fail_alerts controls whether fail alerts are repeated, on consecutive failing checks (defaults to false)

  "preferences": {
  "notifications": {
  "fail_count_alert_threshold": 2,
  "repeat_fail_alerts": false
  }
  }

Backoffs

When a server check fails - the next check will be delayed according to the back-off algorithm. By default, there is no delay (i.e. constant back-off), with a default interval of 10 seconds between checks. When a failing server returns to normal, the check frequency returns to its original value.

Constant

Pinging interval will remain constant. i.e. will not provide any back-off after failure.

Linear

The pinging interval upon failure will be extended linearly. i.e. failure count x pinging interval.

Exponential

With each failure, the subsequent check will be delayed by the last delayed amount, times a multiplier, resulting in time between checks exponentially increasing. The multiplier is set to 2 by default.

Note for Gmail

If there are errors sending email via gmail - enable Access for less secure apps under Account permissions @ https://www.google.com/settings/u/2/security

Deployment

CloudFormation Stacks

See redalert-cloudformation

EC2 & ELB

EC2 & ELB & S3 config

Development

Setup

Dependencies:

• Go dependency manager - glide
• Embedding static assets into binary - go.rice
• protoc for gRPC code generation - gRPC
• Docker-machine for tests

Credits

Rocket emoji via https://github.com/twitter/twemoji

Next Features

See Github Issues here