Unable to reach pi cluster with hostnames on network

Question

I'm currently working on a project using 4 raspberry pi as a cluster. These pi's are attached to each other through a local network, but I need to be able to send command to it from a host computer over wi-fi. Hence they are also configured on the same wi-fi network as the host.

My problem is, is that I can't connect to them through ssh with just their hostname from my laptop. If I use their IP address it works fine, but i'm on a eduroam network so the IP addresses change every 24 hours, so I can't make a script connecting to them based on IP's.

I've tried both ssh and ping using to hostname as such:

ping my_hostname.local
ssh my_hostname.local
ssh pi@my_hostname.local

All of these result in a "Name or service not known" error.

Now having searched the internet far and wide there were several problems that could cause this.

1. Ssh is not enabled on the raspberry pi.
2. Avahi daemon is not running.
3. Avahi daemon is running and should be turned off. (This was a posted solution for post Jessie distro's)

None of these solutions worked though.

The Laptop is running CentOS 7 and the pi's are on the latest Raspbian Stretch release

EDIT: Verbose output of SSH connection:

[mpuls@mitch ~]$ ssh -v epnpi1
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 58: Applying options for *
ssh: Could not resolve hostname epnpi1: Name or service not known
[mpuls@mitch ~]$ ssh -v epnpi1.local
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 58: Applying options for *
ssh: Could not resolve hostname epnpi1.local: Name or service not known
[mpuls@mitch ~]$ ssh -v pi@epnpi1.local
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 58: Applying options for *
ssh: Could not resolve hostname epnpi1.local: Name or service not known
[mpuls@mitch ~]$ ssh -v pi@epnpi1
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 58: Applying options for *
ssh: Could not resolve hostname epnpi1: Name or service not known

Answer 1

You need to use a DNS server to allow all devices on your network to use those hostnames, .local is usually for avahi/bonjour so without that service those hostnames will not work without a DNS server, if you do not want to make a dns server, you can add those entries to your hosts file in the format

ip.address.4.octets name

ex.

192.168.0.23 raspberrypi1
192.168.0.24 raspberrypi2

You will need to add those entries to the host file of all computers accessing the pi's or just use a DNS server

On linux, the hosts file is typically in /etc/hosts