This bundle provides a way to run a series of application related health checks. Health checks in the scope of this bundle go beyond simple actions like performing a ping to a server to see if it's alive. For example a Memcache server can be alive and not displaying any errors in your Nagios but you might not be able to access it from your PHP application. Each health check should then implement some application logic that you want to make sure always works. Another usage can be testing for specific requirements, like availability of PHP extensions.
Another design goal of the bundle was to be able to perform the checks using the same configuration and environment that your application is using. In that way you can make sure that if the health check runs successfully then your app should work too.
So each health check will be a class that will implement the CheckInterface::check
method which must return a CheckResult object. What happens inside that method
is up to the check developer.
Health checks are defined as Symfony services and they have to be tagged as
liip_monitor.check in order to be picked up by the health check runner. This gives
a lot of flexibility to application and bundle developers when they want to add their
own checks.
Checks are run via the command line using a Symfony command or via a REST api that delivers the results in JSON format.
Here's the web interface:
Install with composer:
$ composer require liip/monitor-bundle
Then register the bundle in the AppKernel.php file:
public function registerBundles()
{
$bundles = array(
// ...
new Liip\MonitorBundle\LiipMonitorBundle(),
// ...
);
return $bundles;
}If you want to enable the REST API provided by the bundle then add the following to your routing.yml:
_monitor:
resource: "@LiipMonitorBundle/Resources/config/routing.xml"
prefix: /monitor/healthThen, enable the controller in your configuration:
liip_monitor:
enable_controller: trueAnd finally don't forget to install the bundle assets into your web root:
$ ./app/console assets:install web --symlink --relative
To enable built-in health checks, add them to your config.yml
liip_monitor:
checks:
php_extensions: [apc, xdebug]Once you implemented the class then it's time to register the check service with our service container:
services:
monitor.check.php_extensions:
class: Acme\HelloBundle\Check\PhpExtensionsCheck
arguments:
- [ xhprof, apc, memcache ]
tags:
- { name: liip_monitor.check, alias: php_extensions }The important bit there is to remember to tag your services with the liip_monitor.check tag.
By doing that the check runner will be able to find your checks. Keep in mind that checks
can reside either in your bundles or in your app specific code. The location doesn't matter
as long as the service is properly tagged. The alias is optional and will then simply
define the id used when running health checks individually, otherwise the full service
id must be used in this case.
See "Full Default Config" below for a list of all built-in checks and their configuration.
There are two ways of running the health checks: by using the CLI or by using the REST API provided by the bundle. Let's see what commands we have available for the CLI:
$ ./app/console monitor:list
monitor.check.jackrabbit
monitor.check.redis
monitor.check.memcache
monitor.check.php_extensions
$ ./app/console monitor:health
Jackrabbit Health Check: OK
Redis Health Check: OK
Memcache Health Check: KO - No configuration set for session.save_path
PHP Extensions Health Check: OK
To run an individual check you need to provide the check id to the health command:
$ ./app/console monitor:health monitor.check.php_extensions
PHP Extensions Health Check: OK
To run health checks as a composer post-install or post-update script, simply add the
Liip\\MonitorBundle\\Composer\\ScriptHandler::checkHealth ScriptHandler to the
post-install-cmd / post-update-cmd command sections of your composer.json:
"scripts": {
"post-install-cmd": [
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile",
"Liip\\MonitorBundle\\Composer\\ScriptHandler::checkHealth"
],
"post-update-cmd": [
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile",
"Liip\\MonitorBundle\\Composer\\ScriptHandler::checkHealth"
]
},There are two default reporters: ArrayReporter for the REST API and ConsoleReporter for the CLI command. You can
add additional reporters to be used by either of these.
First, define an additional reporter service and tag it with liip_monitor.additional_reporter:
my_reporter:
class: My\Reporter
tags:
- { name: liip_monitor.additional_reporter, alias: my_reporter }To run additional reporters with the CLI, add --reporter=... options for each one:
$ ./app/console monitor:health --reporter=my_reporter
To run this reporter with the REST API, add a reporters query parameter:
/monitor/health?reporters[]=my_reporter
You can list available reporters with:
$ ./app/console monitor:list --reporters
It is possible to group the health checks for different environments (e.g. application server, cron runner, ...).
If not specified differently, all health checks belong to the default group.
To define groups for built-in health checks, add the following grouping hint to your config.yml:
liip_monitor:
default_group: default
checks:
groups:
default: # checks you may want to execute by default
php_extensions: [apc, xdebug]
cron: # checks you may want to execute only on cron servers
php_extensions: [redis]This creates two groups, default and cron, each having different checks.
To define groups for tagged services, add a group attribute to the respective tags:
services:
monitor.check.php_extensions:
class: Acme\HelloBundle\Check\PhpExtensionsCheck
arguments:
- [ xhprof, apc, memcache ]
tags:
- { name: liip_monitor.check, alias: php_extensions, group: cron }
- { name: liip_monitor.check, alias: php_extensions, group: app_server }Both CLI commands have a --group=... option. If it is not given, the default group is used.
./app/console monitor:list --group=app_server
./app/console monitor:health --group=app_server
Both commands, monitor:list and monitor:health, have an option --all to list or run the checks of all registered
groups. Additionally, the monitor:list has an option --groups to list all registered groups.
liip_monitor:
enable_controller: false
view_template: null
mailer:
enabled: false
recipient: ~ # Required
sender: ~ # Required
subject: ~ # Required
send_on_warning: true
default_group: default
checks:
# Grouping checks
groups:
# Prototype
name:
# Validate that a named extension or a collection of extensions is available
php_extensions: [] # Example: session.use_only_cookies: false
# Pairs of a PHP setting and an expected value
php_flags: # Example: session.use_only_cookies: false
# Prototype
setting: ~
# Pairs of a version and a comparison operator
php_version: # Example: 5.4.15: >=
# Prototype
version: ~
# Process name/pid or an array of process names/pids
process_running: ~ # Example: [apache, foo]
# Validate that a given path (or a collection of paths) is a dir and is readable
readable_directory: [] # Example: ["%kernel.cache_dir%"]
# Validate that a given path (or a collection of paths) is a dir and is writable
writable_directory: [] # Example: ["%kernel.cache_dir%"]
# Validate that a class or a collection of classes is available
class_exists: [] # Example: ["Lua", "My\Fancy\Class"]
# Benchmark CPU performance and return failure if it is below the given ratio
cpu_performance: ~ # Example: 1.0 # This is the power of an EC2 micro instance
# Checks to see if the disk usage is below warning/critical percent thresholds
disk_usage:
warning: 70
critical: 90
path: '%kernel.cache_dir%'
# Checks Symfony2 requirements file
symfony_requirements:
file: '%kernel.root_dir%/SymfonyRequirements.php'
# Checks to see if the OpCache memory usage is below warning/critical thresholds
opcache_memory:
warning: 70
critical: 90
# Checks to see if the APC memory usage is below warning/critical thresholds
apc_memory:
warning: 70
critical: 90
# Checks to see if the APC fragmentation is below warning/critical thresholds
apc_fragmentation:
warning: 70
critical: 90
# Connection name or an array of connection names
doctrine_dbal: null # Example: [default, crm]
# Check if MemCache extension is loaded and given server is reachable
memcache:
# Prototype
name:
host: localhost
port: 11211
# Validate that a Redis service is running
redis:
# Prototype
name:
host: localhost
port: 6379
password: null
# Attempt connection to given HTTP host and (optionally) check status code and page content
http_service:
# Prototype
name:
host: localhost
port: 80
path: /
status_code: 200
content: null
# Attempt connection using Guzzle to given HTTP host and (optionally) check status code and page content
guzzle_http_service:
# Prototype
name:
url: localhost
headers: []
options: []
status_code: 200
content: null
method: GET
body: null
# Validate that a RabbitMQ service is running
rabbit_mq:
# Prototype
name:
host: localhost
port: 5672
user: guest
password: guest
vhost: /
# Checks the version of this app against the latest stable release
symfony_version: ~
# Checks if error pages have been customized for given error codes
custom_error_pages:
error_codes: [] # Required
path: '%kernel.root_dir%'
controller: '%twig.exception_listener.controller%'
# Checks installed composer dependencies against the SensioLabs Security Advisory database
security_advisory:
lock_file: '%kernel.root_dir%/../composer.lock'
# Validate that a stream wrapper or collection of stream wrappers exists
stream_wrapper_exists: [] # Example: ['zlib', 'bzip2', 'zip']
# Find and validate INI files
file_ini: [] # Example: ['path/to/my.ini']
# Find and validate JSON files
file_json: [] # Example: ['path/to/my.json']
# Find and validate XML files
file_xml: [] # Example: ['path/to/my.xml']
# Find and validate YAML files
file_yaml: [] # Example: ['path/to/my.yml']
# PDO connections to check for connection
pdo_connections:
# Prototype
name:
dsn: null
username: null
password: null
timeout: 1
# Checks that fail/warn when given expression is false (expressions are evaluated with symfony/expression-language)
expressions:
# Example:
opcache:
label: OPcache
warning_expression: ini('opcache.revalidate_freq') > 0
critical_expression: ini('opcache.enable')
warning_message: OPcache not optimized for production
critical_message: OPcache not enabled
# Prototype
alias:
label: ~ # Required
warning_expression: null # Example: ini('apc.stat') == 0
critical_expression: null # Example: ini('short_open_tag') == 1
warning_message: null
critical_message: nullFor documentation on the REST API see: http://myproject.org/monitor/health/.
Don't forget to add the bundle routes in your routing.xml file.
You can find a simple Nagios check written in Perl and Python in the Resources/scripts directory.
This is dependent on perl modules available on CPAN Getopt::Std, WWW::Mechanize, and JSON
Copy the script into your scripts directory in Nagios and create a command like this:
define command{
command_name check_symfony_health
command_line $USER1$/check_symfony2.pl -H $HOSTNAME$
}
Running the command with the Hostname flag (-H) will check "http://$HOSTNAME$/monitor/health/run". You can also use the Address flag (-A) to check a specified URL:
command_line $USER1$/check_symfony2.pl -A https://mysite.org/monitor/health/run
The plugin can be used with Authentication, Using the Username (-u) and Password (-p) flags:
command_line $USER1$/check_symfony2.p1 -H $HOSTNAME$ -u username -p password
You can also specify the Warning (-w) and Critical (-c) levels for the check using the standard flags
command_line $USER1$/check_symfony2.pl -H $HOSTNAME$ -w 1 -c 2
Any flags can be combined except -A and -H. THe -u and -p flags should always be used together.
The Python version depends on the nagiosplugin library < 1.0.0.
Copy the script into your scripts directory in Nagios and create a command like this:
define command{
command_name check_symfony_health
command_line $USER1$/check_symfony2.py -w 0 -c 0 -u https://$HOSTNAME$
}
To use the plugin with HTTP basic authentication, change the command to:
command_line $USER1$/check_symfony2.py -w 0 -c 0 -u https://$HOSTNAME$ -a username:password
Add a service:
define service{
hostgroup_name Symfony2
service_description Symfony2 health check
check_command check_symfony_health
use generic-service
}
And create a host attached to the Symfony2 hostgroup:
define host{
use web-host
host_name www.myhost.com
address 8.8.8.4
hostgroups Symfony2
}
And place your host within the Symfony2 hostgroup.