Getting Started

This container it's used to provide workers for Mod Gearman using the Distribute Monitoring approach as you can see in the picture above:

To be able to use this container you need to specify two environment variables at docker run:

• Variable HOSTGROUP define which Nagios hostgroup this worker will use
• Variable SERVER define ip:port of your Gearman server

Basic Example

docker run -d --name gearman-worker \
-e HOSTGROUP=MYHOSTGROUP \
-e SERVER=GEARMANSERVER:GEARMAN_PORT \
bernardovale/mod-gearman-worker

Tags

Tag latest will be always same as minimum. This tag it's the minimal setup required to make this container usable.

Tag oracle increments tag minimum adding Oracle Instant Client and check_oracle_health script

latest

1. mod_gearman_worker
2. check_nrpe
3. check_icmp
4. check_nt

minimum

1. mod_gearman_worker
2. check_nrpe
3. check_icmp
4. check_nt

oracle

1. mod_gearman_worker
2. check_nrpe
3. check_icmp
4. check_nt
5. check_oracle_health
6. Oracle Instant Client 11g

Oracle Client

Container tag oracle has an Oracle Instant Client 11.2 installed whithout tnsnames.ora.

You can provide it as a volume at docker run

On your docker host start a folder to keep your tnsnames.ora

mkdir -p /appliance/oracle

tee /appliance/oracle/tnsnames.ora <<EOF

TESTDB =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.1)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = test)
    )
  )
EOF

Lauch your container and map your tnsnames.ora folder pointing to TNS_ADMIN which is:

/usr/local/instantclient/network/admin

Example of a container with Oracle Client

docker run -d --name gearman-worker \
-e HOSTGROUP=APP \
-e SERVER=GEARMANSERVER:4730 \
-v /appliance/oracle:/usr/local/instantclient/network/admin \
mod-gearman-worker:oracle

Testing the check_oracle_health script

Use the command docker exec to make a quick connection test with an Oracle database.

docker exec gearman-worker bash -c \
"/usr/local/nagios/libexec/check_oracle_health --connect '192.168.0.1:1521/test' \
--username 'system' --password 'mypassword' \
--mode connection-time --warning 1 --critical 5"


OK - 0.07 seconds to connect as SYSTEM | connection_time=0.0676;1;5

Troubleshooting

Error:

CRITICAL: Return code of 127 is out of bounds. Make sure the plugin 
you're trying to run actually exists. (worker: APP)

[/usr/bin/env: /usr/local/nagios/libexec/check_custom_script
: No such file or directory]

```
**Cause** 

You're using a Nagios script that doesn't exists inside the container.

**Solution**

Send the script from your Docker host to the container via [docker cp] (https://docs.docker.com/engine/reference/commandline/cp/).

`docker cp check_custom_script my-container-name:/usr/local/nagios/libexec/check_custom_script`

**OR**

If you think the script it's really important and others may also benefit from it please send my a PR.