Proxmox 5.2 and Host ping connection lost

[jcarnus]

Hi
I have a fully working proxmox 5.2 running container LXC without issue
The server is hosted on OVH and I use the ping to monitor if the server goes well.
Few days ago, I received some false warning of this because suddently the host is not responding anymore to the PING. I've checked all iptables rules and there is no restriction for this
I just would like to know someone has some tips to debug / investigate/ resolved this
Thanks

 

[Alwin]

If you can't ping the machine from a different connection, then get in touch with OVH, they are the only ones that can help you here.

 

[jcarnus]

Hi
Sorry maybe I didnt explain well the issue. I can ping the machine (host) without issue) 99.5% of time. But there is a very small percentage of ping loss. At the beginning, I was thinking this was hardware or network, but If I only setup a debian 9, I dont have this issue. So for me, there is something under proxmox 5.2 that is freezing/loosing network some time to time

 

[Alwin]

What version are you running (pveversion -v)? Does it help to change the kernel?

 

[Bent]

Are you using OVH's built-in monitoring? Because their monitoring is definitely not the best one out there and can easily show false positives.

Additionally using 'ping' to "monitor if the server goes well" is not a very reliable way to monitor things. There are more reliable way out there, Icinga2 being one of them.

That being said, ICMP packages may get discarded on any L3 router(or switch), there is no guarantee it will be delivered. See also <HTTPS>serverfault<DOT>com/questions/297362/icmp-reliability. You can additionally run a check from your server and ping it's gateway at OVH to determine if there are internal connection issues.

 

[jcarnus]

Thanks for your reply. Yes I am using the OVH monitoring but after investigation, i've found that I have some routing issue on the machine.
I cannot understand why all route all duplicated.

Please see below the routing table

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 94.23.202.254 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 94.23.202.254 0.0.0.0 UG 0 0 0 vmbr0
94.23.202.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
94.23.202.0 0.0.0.0 255.255.255.0 U 0 0 0 vmbr0

If I remove the route on eth0, everything works well. Does anyone has an Id why this route on eth0 are added at start time ? Thanks

 

[jcarnus]

root@proxmox:~# pveversion -v
proxmox-ve: 5.2-2 (running kernel: 4.15.17-3-pve)
pve-manager: 5.2-2 (running version: 5.2-2/b1d1c7f4)
pve-kernel-4.15: 5.2-3
pve-kernel-4.15.17-3-pve: 4.15.17-12
corosync: 2.4.2-pve5
criu: 2.11.1-1~bpo90
glusterfs-client: 3.8.8-1
ksm-control-daemon: 1.2-2
libjs-extjs: 6.0.1-2
libpve-access-control: 5.0-8
libpve-apiclient-perl: 2.0-4
libpve-common-perl: 5.0-32
libpve-guest-common-perl: 2.0-16
libpve-http-server-perl: 2.0-9
libpve-storage-perl: 5.0-23
libqb0: 1.0.1-1
lvm2: 2.02.168-pve6
lxc-pve: 3.0.0-3
lxcfs: 3.0.0-1
novnc-pve: 1.0.0-1
proxmox-widget-toolkit: 1.0-18
pve-cluster: 5.0-27
pve-container: 2.0-23
pve-docs: 5.2-4
pve-firewall: 3.0-11
pve-firmware: 2.0-4
pve-ha-manager: 2.0-5
pve-i18n: 1.0-6
pve-libspice-server1: 0.12.8-3
pve-qemu-kvm: 2.11.1-5
pve-xtermjs: 1.0-5
pve-zsync: 1.6-16
qemu-server: 5.0-28
smartmontools: 6.5+svn4324-1
spiceterm: 3.0-5
vncterm: 1.5-3
zfsutils-linux: 0.7.9-pve1~bpo9

 

[jcarnus]

Jun 14 16:02:24 proxmox systemd[1]: Starting Raise network interfaces...
Jun 14 16:02:25 proxmox ifup[1926]: interface dummy0 does not exist!
Jun 14 16:02:25 proxmox ifup[1926]: Waiting for vmbr1 to get ready (MAXWAIT is 2 seconds).
Jun 14 16:02:25 proxmox ifup[1926]: Waiting for vmbr0 to get ready (MAXWAIT is 2 seconds).
Jun 14 16:02:26 proxmox ifup[1926]: RTNETLINK answers: File exists
Jun 14 16:02:26 proxmox ifup[1926]: ifup: failed to bring up vmbr0
Jun 14 16:02:26 proxmox systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Jun 14 16:02:26 proxmox systemd[1]: Failed to start Raise network interfaces.
Jun 14 16:02:26 proxmox systemd[1]: networking.service: Unit entered failed state.
Jun 14 16:02:26 proxmox systemd[1]: networking.service: Failed with result 'exit-code'.

 

[jcarnus]

With debian 9, I have an issue where eth0 (or other) and vmbr0 get the IP assigned. This is what is troubling the routing table

2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr0 state UP group default qlen 1000
link/ether 08:60:6e:e5:c0:47 brd ff:ff:ff:ff:ff:ff
inet 192.99.7.148/24 brd 192.99.7.255 scope global enp3s0
valid_lft forever preferred_lft forever
3: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 08:60:6e:e5:c0:47 brd ff:ff:ff:ff:ff:ff
inet 192.99.7.148/24 brd 192.99.7.255 scope global vmbr0
valid_lft forever preferred_lft forever
inet6 2607:5300:60:3894::/64 scope global
valid_lft forever preferred_lft forever
inet6 fe80::a60:6eff:fee5:c047/64 scope link
valid_lft forever preferred_lft forever

 

[Bent]

mind posting your config in:

/etc/network/interfaces

 

[jcarnus]

I think I've found the issue. Can anyone from proxmox can confirm me this cannot work like this:

cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# for Routing
auto vmbr1
iface vmbr1 inet manual
bridge_ports dummy0
bridge_stp off
bridge_fd 0


# vmbr0: Bridging. Make sure to use only MAC adresses that were assigned to you.
auto vmbr0
iface vmbr0 inet static
address 94.23.202.16/24
gateway 94.23.202.254
bridge_ports eth0
bridge_stp off
bridge_fd 0

AND
cat /etc/systemd/network/50-default.network
# This file sets the IP configuration of the primary (public) network device.
# You can also see this as "OSI Layer 3" config.
# It was created by the OVH installer, please be careful with modifications.
# Documentation: man systemd.network or https://www.freedesktop.org/software/systemd/man/systemd.network.html

[Match]
MACAddress=0c:c4:7a:06:ae:4c

[Network]
Description=network interface on public network, with default route
DHCP=no
Address=94.23.xxxx/24
Gateway=94.23.xxxx.254
#IPv6AcceptRA=false
NTP=ntp.ovh.net
DNS=127.0.0.1
DNS=213.186.33.99
DNS=2001:41d0:3:163::1
Gateway=2001:41d0:0002:4dff:ff:ff:ff:ff

[Address]
Address=2001:41d0:0002:4d10::/64

[Route]
Destination=2001:41d0:0002:4dff:ff:ff:ff:ff
Scope=link

 

[kotakomputer]

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 94.23.202.254 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 94.23.202.254 0.0.0.0 UG 0 0 0 vmbr0
94.23.202.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
94.23.202.0 0.0.0.0 255.255.255.0 U 0 0 0 vmbr0

Just remove the double routing.
BTW, eth0 is not default naming since Proxmox 5.2, its using new format like "enp3s0" as shown in your debian config.