Follow the steps below to assign or change the IP address on the management interface on a Arista swtich.

localhost> en
localhost# configure
localhost(config)# interface management 1
localhost(config-if-Ma1)# ip address 192.168.57.2/24
localhost(config-if-Ma1)# show active
interface Management 1
    ip address 192.168.57.2/24
localhost(config-if-Ma1)# exit
localhost(config)# exit
localhost# copy running-config startup-config