[Heartbeat] root privileges required for ICMP

[fkelbert]

It seems root privileges are required to execute the following monitor:

- type: icmp
  hosts: [ "google.co.uk", "8.8.8.8" ]
  schedule: '@every 10s'

When running without root privileges, heartbeat fails with the following message: Exiting: could not create monitor: job err failed to initiate IPv4 support

I propose to:

• include a hint towards missing root privileges
• extend the documentation accordingly

[elasticmachine]

Pinging @elastic/uptime

[andrewvc]

I agree, the error message is terrible. We should work on it.

Even more ideally, we could research using capabilities instead of root access to let people run with the minimum of necessary privileges.

[leopucci]

I've added log messages and unprivileged icmp access.
failed to initiate IPv4 support. Check log details for permission configuration

You dont have root permission to run ping. You can run without root by setting cap_net_raw:
sudo setcap cap_net_raw+eip /path/to/heartbeat
Your system allows the use of unprivileged ping by setting net.ipv4.ping_group_range
sysctl -w net.ipv4.ping_group_range='<min-uid> <max-uid>' 

- Non-root execution (preferred)
Setting CAP_NET_RAW on file
Can be set by executing setcap cap_net_raw+ep /path/to/heartbeat to make raw socket available

- Unprivileged icmp access (implemented on kernel since ~2010)
Available for Linux/Mac OS darwin:
sysctl -w net.ipv4.ping_group_range="0 100"
After allowing group ids, users can use unpriveleged icmp socket

[andrewvc]

Fixed with #13795