Containers unable to ping anything

manojnc · June 13, 2020, 11:22pm

Hello All,

I need help with resolving a possible network configuration of the containers that I am launching from remote image repo. Here is the details of the situation

I created two images, one from images.linuxcontainers.com and another from ubuntu official.

lxc launch images:fedora/32 fedora1
lxc launch ubuntu:18.04 ubuntu1

When I do a list , i only see that ubuntu image is assigned a IPV4 and I can only ping outside network resource from ubuntu containers and not the fedora.

[root@fedora1 ~]# curl -I google.com
curl: (6) Could not resolve host: google.com

[root@fedora1 ~]# ping 8.8.8.8
ping: connect: Network is unreachable

Both the containers are created from the same default profile, so the network bridge details is not different for these two containers. I cannot understand why only fedora container is unable to communicate via network. Any help is greatly appreciated.

tomp · June 15, 2020, 7:31am

Please show the output of lxc config show <container> --expanded for each container, also ip a and ip r inside each container and on the host. Thanks

manojnc · June 15, 2020, 9:03am

Hello @tomp , Thanks for your response

Please see the following details.

Fedora1 --> problematic container

root@ubuntu1:/home/manoj# lxc config show fedora1 --expanded
architecture: x86_64
config:
image.architecture: amd64
image.description: Fedora 32 amd64 (20200612_20:33)
image.os: Fedora
image.release: “32”
image.serial: “20200612_20:33”
volatile.base_image: 8541c1b494fba046f32119ac4c3d7a82c28176bd9c43af7de464557e62ded207
volatile.eth0.hwaddr: 00:16:3e:fa:37:be
volatile.idmap.base: “0”
volatile.idmap.next: ‘[{“Isuid”:true,“Isgid”:false,“Hostid”:100000,“Nsid”:0,“Maprange”:65536},{“Isuid”:false,“Isgid”:true,“Hostid”:100000,“Nsid”:0,“Maprange”:65536}]’
volatile.last_state.idmap: ‘[{“Isuid”:true,“Isgid”:false,“Hostid”:100000,“Nsid”:0,“Maprange”:65536},{“Isuid”:false,“Isgid”:true,“Hostid”:100000,“Nsid”:0,“Maprange”:65536}]’
volatile.last_state.power: RUNNING
devices:
eth0:
name: eth0
nictype: bridged
parent: lxdbr0
type: nic
root:
path: /
pool: default
type: disk
ephemeral: false
profiles:

default
stateful: false
description: “”
root@ubuntu1:/home/manoj#

[root@fedora1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 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
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
5: eth0@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 00:16:3e:fa:37:be brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet6 fd42:f3a0:baa1:e724:216:3eff:fefa:37be/64 scope global dynamic mngtmpaddr
valid_lft 3541sec preferred_lft 3541sec
inet6 fe80::216:3eff:fefa:37be/64 scope link
valid_lft forever preferred_lft forever

[root@fedora1 ~]# ip r
[root@fedora1 ~]#

on HOST

root@ubuntu1:/home/manoj# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 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
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1460 qdisc fq_codel state UP group default qlen 1000
link/ether 42:01:0a:8a:00:0a brd ff:ff:ff:ff:ff:ff
inet 10.138.0.10/32 scope global dynamic ens4
valid_lft 1830sec preferred_lft 1830sec
inet6 fe80::4001:aff:fe8a:a/64 scope link
valid_lft forever preferred_lft forever
4: lxdbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether fe:4c:79:c5:b6:31 brd ff:ff:ff:ff:ff:ff
inet 10.142.142.1/24 scope global lxdbr0
valid_lft forever preferred_lft forever
inet6 fd42:f3a0:baa1:e724::1/64 scope global
valid_lft forever preferred_lft forever
inet6 fe80::5486:52ff:fe32:900c/64 scope link
valid_lft forever preferred_lft forever
6: vethSW7E0K@if5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master lxdbr0 state UP group default qlen 1000
link/ether fe:4c:79:c5:b6:31 brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet6 fe80::fc4c:79ff:fec5:b631/64 scope link
valid_lft forever preferred_lft forever

root@ubuntu1:/home/manoj# ip r
default via 10.138.0.1 dev ens4 proto dhcp src 10.138.0.10 metric 100
10.138.0.1 dev ens4 proto dhcp scope link src 10.138.0.10 metric 100
10.142.142.0/24 dev lxdbr0 proto kernel scope link src 10.142.142.1

Details for container that is working as expected

root@ubuntu1:/home/manoj# lxc config show centos1 --expanded
architecture: x86_64
config:
image.architecture: amd64
image.description: Centos 8 amd64 (20200613_07:08)
image.os: Centos
image.release: “8”
image.serial: “20200613_07:08”
volatile.base_image: 06e855ac499398d24bcba3c1ca5dfa56e409c07b2f3cef14b6f76b42cf5b3d6f
volatile.eth0.hwaddr: 00:16:3e:7d:9c:a3
volatile.idmap.base: “0”
volatile.idmap.next: ‘[{“Isuid”:true,“Isgid”:false,“Hostid”:100000,“Nsid”:0,“Maprange”:65536},{“Isuid”:false,“Isgid”:true,“Hostid”:100000,“Nsid”:0,“Maprange”:65536}]’
volatile.last_state.idmap: ‘[{“Isuid”:true,“Isgid”:false,“Hostid”:100000,“Nsid”:0,“Maprange”:65536},{“Isuid”:false,“Isgid”:true,“Hostid”:100000,“Nsid”:0,“Maprange”:65536}]’
volatile.last_state.power: RUNNING
devices:
eth0:
name: eth0
nictype: bridged
parent: lxdbr0
type: nic
root:
path: /
pool: default
type: disk
ephemeral: false
profiles:

default
stateful: false
description: “”

[root@centos1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 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
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
13: eth0@if14: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 00:16:3e:7d:9c:a3 brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet 10.142.142.88/24 brd 10.142.142.255 scope global dynamic noprefixroute eth0
valid_lft 740sec preferred_lft 740sec
inet6 fd42:f3a0:baa1:e724:216:3eff:fe7d:9ca3/64 scope global dynamic mngtmpaddr noprefixroute
valid_lft 3335sec preferred_lft 3335sec
inet6 fe80::216:3eff:fe7d:9ca3/64 scope link noprefixroute
valid_lft forever preferred_lft forever

[root@centos1 ~]# ip r
default via 10.142.142.1 dev eth0 proto dhcp metric 100
10.142.142.0/24 dev eth0 proto kernel scope link src 10.142.142.88 metric 100
[root@centos1 ~]#