Guys about LXC running with your old LXC instance. First change the lxc.conf from the /srv/lxc to the path you used before.
In my case the path was /mnt/LXC referring to my mSATA ssd.
Do fix the mounting first. LXC directory in the mnt i created it with the mkdir command. (mkdir /mnt/LXC)
Although in luci it now recognized you having the LXC (sees the config file), it cannot start the LXC instance.
root@K-Router:/mnt/LXC/K-Router-LXC# lxc-start -n K-Router-LXC
The configuration file contains legacy configuration keys.
Please update your configuration file!
lxc-start: K-Router-LXC: lxccontainer.c: wait_on_daemonized_start: 760 Received container state "STOPPING" instead of "RUNNING"
lxc-start: K-Router-LXC: tools/lxc_start.c: main: 371 The container failed to start.
lxc-start: K-Router-LXC: tools/lxc_start.c: main: 373 To get more details, run the container in foreground mode.
lxc-start: K-Router-LXC: tools/lxc_start.c: main: 375 Additional information can be obtained by setting the --logfile and --logpriority options.You need to update the config file of your lxc instance. You can find this in PATH/LXC Directory/config file.
In my case it was /mnt/LXC/K-Router-LXC/
Use this url to adjust your setting to version 2.1 as the version we used in TOS 3.X was based on LXC 1.5, which used different configuration settings.
https://linuxcontainers.org/lxc/manpages/man5/lxc.container.conf.5.html
Your config should look something like this.
New LXC config file
# Template used to create this container: /usr/share/lxc/templates/lxc-download
# Parameters passed to the template: --server repo.turris.cz/lxc --dist Ubuntu --release Bionic --arch armv7l
# For additional config options, please look at lxc.container.conf(5)
# Debian workaround
# Template to generate fixed MAC address
Distribution configuration
lxc.arch = armv7l
Container specific configuration
lxc.tty.max = 4
lxc.pty.max = 1024
lxc.rootfs.path = /mnt/LXC/K-Router-LXC/rootfs
lxc.uts.name = K-Router-LXC
Network configuration
lxc.net.0.type = veth
lxc.net.0.link = br-lan
lxc.net.0.flags = up
lxc.net.0.name = eth0
lxc.net.0.ipv4.address = <IP ADDRESS>/24
lxc.net.0.ipv4.gateway = <GATEWAY>
lxc.net.0.script.up = /usr/share/lxc/hooks/tx-off
lxc.net.0.hwaddr = <hwaddr>
Although solved the first problem, now i am being stopped by another error.
lxc-start K-Router-LXC 20190316122303.532 ERROR lxc_conf - conf.c:run_buffer:438 - Script exited with status 127.
lxc-start K-Router-LXC 20190316122303.590 ERROR lxc_network - network.c:lxc_create_network_priv:2402 - Failed to create network device
lxc-start K-Router-LXC 20190316122303.590 ERROR lxc_start - start.c:lxc_spawn:1206 - Failed to create the network.
lxc-start K-Router-LXC 20190316122303.590 ERROR lxc_start - start.c:__lxc_start:1459 - Failed to spawn container "K-Router-LXC".
lxc-start K-Router-LXC 20190316122303.590 ERROR lxc_container - lxccontainer.c:wait_on_daemonized_start:760 - Received container state "STOPPING" instead of "RUNNING"
lxc-start K-Router-LXC 20190316122303.591 ERROR lxc_start_ui - tools/lxc_start.c:main:371 - The container failed to start.
lxc-start K-Router-LXC 20190316122303.591 ERROR lxc_start_ui - tools/lxc_start.c:main:373 - To get more details, run the container in foreground mode.
lxc-start K-Router-LXC 20190316122303.591 ERROR lxc_start_ui - tools/lxc_start.c:main:375 - Additional information can be obtained by setting the --logfile and -- logpriority options.