Support for speedtest-cli App for unix-agent added

Here is the support for SPEEDTEST® by OOKLA®

https://www.speedtest.net/de/apps/cli

How To:

• install speedtest cli as documented on ookla's website
• add new cronjob for recurring speedtest
• be happy about your bandwidth statistics

cronjob to run every 5 minutes:

1,6,11,16,21,26,31,36,41,46,51,56 * * * * root /usr/bin/speedtest -f json-pretty > /tmp/speedtest.json

alternatively every 15 minutes:

1,16,31,46 * * * * root /usr/bin/speedtest -f json-pretty > /tmp/speedtest.json

or every hour:

1 * * * * root /usr/bin/speedtest -f json-pretty > /tmp/speedtest.json

Note: Don't run it together with OBS poller.php! Because the unix-agent will read an empty speedtest.json, because the test takes some seconds to complete