[Lxc-users] Slow response times (at least, from the LAN) to LXC containers

Michael B. Trausch mike at trausch.us
Wed Mar 10 06:32:24 UTC 2010


Hello,

Alright, so I am still having some strange networking issues between my 
LAN and my containers.  I'm not sure if the outside world is having 
trouble with my containers or not, though.

Here's the situation:  I have 3 containers running under LXC, all of 
which have unique MAC addresses (I checked this time...!  I still feel 
like an idiot after the last email I sent here...).  2 of these 
addresses are static, and two are DHCP (the DHCP addresses are LAN 
addresses in the 172.16.0.0/24 network, and the other ones are global IP 
addresses).

Now, I am _not_ having any issues with the LAN addresses.  Those, in 
fact, are working just fine.  The problem I am having is that the 
containers that have global IP addresses are having issues; they will 
always (eventually) reply, but sometimes they simply fail to respond and 
I have not the slightest clue why.  This is the only thing that I could 
get working under OpenVZ that I cannot seem to get working correctly here.

Here is ping output showing the problem:

mbt at fennel:~$ time ping -c 4 spicerack.trausch.us
PING spicerack.trausch.us (173.15.213.185) 56(84) bytes of data.
 From 172.16.0.1: icmp_seq=2 Redirect Host(New nexthop: 173.15.213.185)
 From 172.16.0.1: icmp_seq=3 Redirect Host(New nexthop: 173.15.213.185)
64 bytes from 173.15.213.185: icmp_seq=4 ttl=64 time=2.27 ms

--- spicerack.trausch.us ping statistics ---
4 packets transmitted, 1 received, 75% packet loss, time 11073ms
rtt min/avg/max/mdev = 2.278/2.278/2.278/0.000 ms

real	0m21.144s
user	0m0.000s
sys	0m0.020s

Now, this is pinging from my laptop.  When I ping from the outside 
world, it always seems to work:

otaku% time ping -c 4 spicerack.trausch.us
PING spicerack.trausch.us (173.15.213.185): 56 data bytes
64 bytes from 173.15.213.185: icmp_seq=0 ttl=44 time=42.237 ms
64 bytes from 173.15.213.185: icmp_seq=1 ttl=44 time=60.862 ms
64 bytes from 173.15.213.185: icmp_seq=2 ttl=44 time=49.686 ms
64 bytes from 173.15.213.185: icmp_seq=3 ttl=44 time=50.719 ms

----spicerack.trausch.us PING Statistics----
4 packets transmitted, 4 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 42.237/50.876/60.862/7.655 ms
ping -c 4 spicerack.trausch.us  0.01s user 0.01s system 0% cpu 3.067 total

I don't understand why this is.  This problem also exhibits itself when 
I try to go to my Web server (on that very same IP address).  It will 
_always_ fail to connect the first time, and then I can reload and get 
to it the second.  If I stop going through page-load cycles with the 
machine, then I have the same problem again in a few minutes.

The networking is all bridged like so (from the container host, obviously):

mbt at saffron:~$ ifconfig
br0       Link encap:Ethernet  HWaddr 00:e0:4d:c6:99:c3
           inet addr:172.16.0.2  Bcast:172.16.0.255  Mask:255.255.255.0
           inet6 addr: fe80::2e0:4dff:fec6:99c3/64 Scope:Link
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
           RX packets:1338484 errors:0 dropped:0 overruns:0 frame:0
           TX packets:94110 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0
           RX bytes:233020157 (233.0 MB)  TX bytes:13305287 (13.3 MB)

eth1      Link encap:Ethernet  HWaddr 00:e0:4d:c6:99:c3
           inet6 addr: fe80::2e0:4dff:fec6:99c3/64 Scope:Link
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
           RX packets:8304537 errors:0 dropped:0 overruns:0 frame:0
           TX packets:8319870 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:5506717265 (5.5 GB)  TX bytes:5028941992 (5.0 GB)
           Interrupt:27 Base address:0x4000

lo        Link encap:Local Loopback
           inet addr:127.0.0.1  Mask:255.0.0.0
           inet6 addr: ::1/128 Scope:Host
           UP LOOPBACK RUNNING  MTU:16436  Metric:1
           RX packets:17 errors:0 dropped:0 overruns:0 frame:0
           TX packets:17 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0
           RX bytes:1426 (1.4 KB)  TX bytes:1426 (1.4 KB)

veth7XAGMJ Link encap:Ethernet  HWaddr 66:43:3e:f1:49:50
           inet6 addr: fe80::6443:3eff:fef1:4950/64 Scope:Link
           UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
           RX packets:4667350 errors:0 dropped:0 overruns:0 frame:0
           TX packets:6883287 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:3822200715 (3.8 GB)  TX bytes:7370222136 (7.3 GB)

vethZ2MPrI Link encap:Ethernet  HWaddr a2:79:e0:7d:c9:32
           inet6 addr: fe80::a079:e0ff:fe7d:c932/64 Scope:Link
           UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
           RX packets:239273 errors:0 dropped:0 overruns:0 frame:0
           TX packets:2005271 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:173986823 (173.9 MB)  TX bytes:304727044 (304.7 MB)

vethlyeclR Link encap:Ethernet  HWaddr 06:c1:72:45:84:6b
           inet6 addr: fe80::4c1:72ff:fe45:846b/64 Scope:Link
           UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
           RX packets:1012517 errors:0 dropped:0 overruns:0 frame:0
           TX packets:2705478 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:202961661 (202.9 MB)  TX bytes:326251397 (326.2 MB)

vethpzG08i Link encap:Ethernet  HWaddr ae:85:18:6c:f2:b8
           inet6 addr: fe80::ac85:18ff:fe6c:f2b8/64 Scope:Link
           UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
           RX packets:1848591 errors:0 dropped:0 overruns:0 frame:0
           TX packets:2750421 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:619641970 (619.6 MB)  TX bytes:363396089 (363.3 MB)

virbr0    Link encap:Ethernet  HWaddr f2:3f:6e:49:77:df
           inet addr:192.168.122.1  Bcast:192.168.122.255 
Mask:255.255.255.0
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
           RX packets:0 errors:0 dropped:0 overruns:0 frame:0
           TX packets:77 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0
           RX bytes:0 (0.0 B)  TX bytes:7703 (7.7 KB)

mbt at saffron:~$ sudo brctl show
bridge name	bridge id		STP enabled	interfaces
br0		8000.00e04dc699c3	yes		eth1
							veth7XAGMJ
							vethZ2MPrI
							vethlyeclR
							vethpzG08i
virbr0		8000.000000000000	yes		

What I don't get is why I am receiving these redirects from ping.  I 
never get them when pinging 172.16.0.x addresses that are in LXC 
containers on that system.  And I never got these redirects before when 
I was running containers in OpenVZ.

Also, if I try to ping that same interface's IPv6 addresses, I get 
failures (Address unreachable), no matter if I ping the private or the 
global one.  However, I can reach ipv6.google.com just fine, and it is 
going through that computer to get to my tunnel to Hurricane Electric. 
It has to, since that container is my only IPv6 route to the world and 
the tunnel endpoint is that container's global IP address.

I am completely confused on this one.  I don't know where to look next. 
  Please help.  Thank you.

	--- Mike

-- 
Michael B. Trausch                                    ☎ (404) 492-6475




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