[dhcpv6_relay] Fix dependency of dhcp-mon on VLAN with only v6 cfg is provided

[vivekrnv]

Signed-off-by: Vivek Reddy Karri [email protected]

Why I did it

1. config vlan add 100
2. config vlan member add Ethernet0
3. config interface ip add Vlan100 <ip_addr>
4. config load

{
        "DHCP_RELAY" :{
                "Vlan100" : {
                        "dhcpv6_servers" : ["fc02:2000::2"]
                }
        }
}

5. Systemctl restart dhcp_relay

Behavior Seec

1. dhcp_relay container doesn't start with the following log

Dec  8 21:19:47.779998 sonic  INFO dockerd[572]: time="2022-12-08T21:19:47.779415981+02:00" level=error msg="Error setting up exec command in container dhcp_relay: Container 4a64823d9a9a3617f5fdb8f9b54a10e6ebf003df1c3dafeea1606ca38a9ae0d8 is not running"

2. Happened because of the wrong jinja formatting of supervisord.conf file which results in:

root@sonic:/home/admin# sonic-cfggen -d -t docker-dhcp-relay.supervisord.conf.j2
..............
..............

[group:dhcp-relay]
programs=dhcp6relay

[program:dhcp6relay]
command=/usr/sbin/dhcp6relay
priority=3
autostart=false
autorestart=false
stdout_logfile=syslog
stderr_logfile=syslog
dependent_startup=true
dependent_startup_wait_for=start:exited

[group:dhcpmon]
programs=dhcpmon-Vlan100

<missing [program:dhcp6relay] section for dhcpmon>

root@sonic:/home/admin#

With this change, the formatting is proper and the container starts as expected even without VLAN| dhcp6_servers field

[group:dhcp-relay]
programs=dhcp6relay

[program:dhcp6relay]
command=/usr/sbin/dhcp6relay
priority=3
autostart=false
autorestart=false
stdout_logfile=syslog
stderr_logfile=syslog
dependent_startup=true
dependent_startup_wait_for=start:exited

[group:dhcpmon]
programs=dhcpmon-Vlan100

[program:dhcpmon-Vlan100]
command=/usr/sbin/dhcpmon -id Vlan100 -iu Ethernet236 -im eth0
priority=4
autostart=false
autorestart=false
stdout_logfile=syslog
stderr_logfile=syslog
dependent_startup=true
dependent_startup_wait_for=

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205
• 202211

Description for the changelog

Ensure to add label/tag for the feature raised. example - PR#2174 under sonic-utilities repo. where, Generic Config and Update feature has been labelled as GCU.

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[dgsudharsan]

@kellyyeh @jcaiMR @yxieca Can you please review this fix?

[dgsudharsan]

@kellyyeh @jcaiMR @yxieca Can we please merge this?

[mssonicbld]

Cherry-pick PR to 202205: #13029

[liuh-80]

202012 branch PR merged: #13040

[mssonicbld]

Cherry-pick PR to 202211: #13634