webssh connectivity when graphite is launched outside of clab yaml

[bortok]

If graphite is launched via "docker run" instead of from clab yaml, it ends up connected to a different bridge – this breaks webssh connectivity to emulated nodes. For example,

+---+------------------------+--------------+-----------------------------+-------+---------+---------------+--------------+
| # |          Name          | Container ID |            Image            | Kind  |  State  | IPv4 Address  | IPv6 Address |
+---+------------------------+--------------+-----------------------------+-------+---------+---------------+--------------+
| 1 | clab-h84_clab-centos1  | 965ef2bb8397 | nanoghackathon82/centos     | linux | running | 172.22.0.3/24 | N/A          |
| 2 | clab-h84_clab-centos2  | 233a38b80e07 | nanoghackathon82/centos     | linux | running | 172.22.0.5/24 | N/A          |

while

docker exec -it graphite sh
/usr/local/webssh2 # ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
78: eth0@if79: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue state UP
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
       valid_lft forever preferred_lft forever

/usr/local/webssh2 # ping 172.22.0.1
PING 172.22.0.1 (172.22.0.1): 56 data bytes
64 bytes from 172.22.0.1: seq=0 ttl=64 time=0.062 ms
64 bytes from 172.22.0.1: seq=1 ttl=64 time=0.106 ms
^C
--- 172.22.0.1 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss

ping 172.22.0.3
PING 172.22.0.3 (172.22.0.3): 56 data bytes
^C
--- 172.22.0.3 ping statistics ---
2 packets transmitted, 0 packets received, 100% packet loss

Looks like this happens to do lack of a return route from the emulated nodes back to graphite IP address.