[Rhel + Rocky] Remove route mertic from NetworkManager

[himani2411]

Description of changes

• Remove route metric from NetworkManager

Addition of route-metric would add clashing routes in terms of the priority given for the 2 NICs, which is why some tests pass and the other fails. This happens on the HN where the NI 0 is default one which has the elastic public IP
Clashing route metrics would cause below errors in connecting to endpoints.

ERROR - Failed when getting instance info from EC2 with exception Connect timeout on endpoint URL: "https://ec2.us-east-1.amazonaws.com/"

IP Table of Parallelcluster 3.12.0 where the NI 0 has the highest priority and NI 1 has the 2nd highest priority

 ip route show table main
default via <IP-IG> dev eth0 proto dhcp src 192.168.23.21 metric 100 # N1 0 
default via <IP-IG> dev eth1 proto dhcp src 192.168.17.156 metric 101  # N1 1
default via <IP-IG> dev eth0 metric 1000 # PC added 
default via <IP-IG> dev eth1 metric 1001  # PC added 
 <IP-IG>/20 dev eth0 proto kernel scope link src 192.168.23.21 metric 100
 <IP-IG>/20 dev eth1 proto kernel scope link src 192.168.17.156 metric 101

IP Table of 3.13.0

default via  <IP-IG> dev eth1 proto dhcp src 192.168.17.156 metric 100 # clashes with the NI 0 line below
default via  <IP-IG> dev eth0 proto dhcp src 192.168.23.21 metric 100 
default via <IP-IG> dev eth1 proto dhcp src 192.168.17.156 metric 101
default via <IP-IG> dev eth0 metric 1000 # PC added 
default via <IP-IG> dev eth1 metric 1101  # PC added 
<IP-IG>/20 dev eth0 proto kernel scope link src 192.168.23.21 metric 100
<IP-IG>/20 dev eth1 proto kernel scope link src 192.168.17.156 metric 100 # clashes with the NI 0 line above
<IP-IG>/20 dev eth1 proto kernel scope link src 192.168.17.156 metric 101

Tests

ONGOING

test-suites:
  multiple_nics:
    test_multiple_nics.py::test_multiple_nics:
      dimensions:
        - regions: ["use1-az1"]
          instances: ["c6in.32xlarge"]
          oss: ["rhel8", "rhel9", "rocky8", "rocky9"]
          schedulers: ["slurm"]

References

• Link to impacted open issues.
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