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Posted to users@cloudstack.apache.org by Indra Pramana <in...@sg.or.id> on 2016/04/30 22:00:07 UTC

regular disconnection every 2-3 mins on haproxy cloudstack mgmt server LB implementation

Dear all,

We are running CloudStack 4.2.0 with KVM hypervisor and Ceph RBD storage.
We implemented secondary CloudStack management server and haproxy load
balancer, and tonight we changed our configuration so that the CloudStack
agents will be connecting to the LB IP rather than the CS mgmt server
directly.

However, we noted that the agent will be regularly disconnected every 2-3
minutes. Here are the excerpts on the agent.log:

====
2016-05-01 01:30:10,982 DEBUG [utils.nio.NioConnection]
(Agent-Selector:null) Location 1: Socket
Socket[addr=/X.X.X.8,port=8250,localport=50613] closed on read.  Pro
bably -1 returned: Connection closed with -1 on reading size.
2016-05-01 01:30:10,983 DEBUG [utils.nio.NioConnection]
(Agent-Selector:null) Closing socket
Socket[addr=/X.X.X.8,port=8250,localport=50613]
2016-05-01 01:30:10,983 DEBUG [cloud.agent.Agent] (Agent-Handler-3:null)
Clearing watch list: 2
2016-05-01 01:30:15,984 INFO  [cloud.agent.Agent] (Agent-Handler-3:null)
Lost connection to the server. Dealing with the remaining commands...
2016-05-01 01:30:20,985 INFO  [cloud.agent.Agent] (Agent-Handler-3:null)
Reconnecting...
2016-05-01 01:30:20,986 INFO  [utils.nio.NioClient] (Agent-Selector:null)
Connecting to X.X.X.8:8250
2016-05-01 01:30:21,101 INFO  [utils.nio.NioClient] (Agent-Selector:null)
SSL: Handshake done
2016-05-01 01:30:21,101 INFO  [utils.nio.NioClient] (Agent-Selector:null)
Connected to X.X.X.8:8250
2016-05-01 01:30:21,133 DEBUG [kvm.resource.LibvirtCapXMLParser]
(Agent-Handler-1:null) Found /usr/bin/kvm as a suiteable emulator
2016-05-01 01:30:21,134 DEBUG [kvm.resource.LibvirtComputingResource]
(Agent-Handler-1:null) Executing: /bin/bash -c qemu-img --help|grep convert
2016-05-01 01:30:21,152 DEBUG [kvm.resource.LibvirtComputingResource]
(Agent-Handler-1:null) Execution is successful.
2016-05-01 01:30:21,152 DEBUG [kvm.resource.LibvirtComputingResource]
(Agent-Handler-1:null)   convert [-c] [-p] [-q] [-n] [-f fmt] [-t cache]
[-T src_cache] [-O output
_fmt] [-o options] [-s snapshot_id_or_name] [-l snapshot_param] [-S
sparse_size] filename [filename2 [...]] output_filename
    options are: 'none', 'writeback' (default, except for convert),
'writethrough',
    'directsync' and 'unsafe' (default for convert)
====

and then it will reconnected again, and then got disconnected again, etc.
It will continue on that loop.

haproxy.cfg configuration for the NIC facing the hypervisors:

====
listen cloudstack_systemvm_8250
bind X.X.X.8:8250
mode tcp
option tcplog
balance source
server management-server-01.xxx.com X.X.X.3:8250 maxconn 32 check
server management-server-02.xxx.com X.X.X.6:8250 maxconn 32 check
====

Note that .3 and .6 are the first and second CloudStack management servers
respectively, while .8 is the IP of the load balancer. We are using one LB
at the moment.

Nothing much is found on the haproxy.log, see below.

====
May  1 01:14:41 cs-haproxy-02 haproxy[923]: X.X.X.28:50401
[01/May/2016:01:12:50.803] cloudstack_systemvm_8250
cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/110340 8584 cD
0/0/0/0/0 0/0
May  1 01:15:46 cs-haproxy-02 haproxy[923]: X.X.X.28:50402
[01/May/2016:01:14:51.150] cloudstack_systemvm_8250
cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/54920 8234 cD
0/0/0/0/0 0/0
May  1 01:16:47 cs-haproxy-02 haproxy[923]: X.X.X.28:50403
[01/May/2016:01:15:56.075] cloudstack_systemvm_8250
cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/51344 7868 cD
0/0/0/0/0 0/0
May  1 01:17:48 cs-haproxy-02 haproxy[923]: X.X.X.28:50404
[01/May/2016:01:16:57.426] cloudstack_systemvm_8250
cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50854 7630 cD
0/0/0/0/0 0/0
May  1 01:18:49 cs-haproxy-02 haproxy[923]: X.X.X.28:50405
[01/May/2016:01:17:58.285] cloudstack_systemvm_8250
cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50955 7630 cD
0/0/0/0/0 0/0
May  1 01:24:49 cs-haproxy-02 haproxy[923]: X.X.X.28:50406
[01/May/2016:01:18:59.245] cloudstack_systemvm_8250
cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/350361 14638 cD
0/0/0/0/0 0/0
May  1 01:28:00 cs-haproxy-02 haproxy[923]: X.X.X.28:50571
[01/May/2016:01:27:09.638] cloudstack_systemvm_8250
cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50602 2852 cD
0/0/0/0/0 0/0
May  1 01:30:11 cs-haproxy-02 haproxy[923]: X.X.X.28:50613
[01/May/2016:01:29:20.260] cloudstack_systemvm_8250
cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50876 7630 cD
0/0/0/0/0 0/0
May  1 01:32:11 cs-haproxy-02 haproxy[923]: X.X.X.28:50614
[01/May/2016:01:30:21.142] cloudstack_systemvm_8250
cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/110308 8870 cD
0/0/0/0/0 0/0
====

Note that .28 is the IP address of the hypervisor I tested to connect to
the LB IP. Did I missed out anything on the haproxy configuration? Any
advice is greatly appreciated.

Looking forward to your reply, thank you.

Cheers.

Re: regular disconnection every 2-3 mins on haproxy cloudstack mgmt server LB implementation

Posted by Remi Bergsma <RB...@schubergphilis.com>.
You're welkome! Great to hear it now works :-)

Sent from my iPhone

> On 30 Apr 2016, at 23:13, Indra Pramana <in...@sg.or.id> wrote:
> 
> Hi Remi,
> 
> Many thanks for your tips! You are right indeed, by default haproxy has
> timeout set to 50 seconds (or 50,000ms). I changed it to 120 seconds (2
> minutes) and have monitored the agent connection and it's no longer
> flapping. Monitoring now and will let you know if there are any further
> issues.
> 
> On /etc/haproxy/haproxy.cfg, modify this under defaults section:
> 
>        timeout client  120000
>        timeout server  120000
>        #timeout client  50000
>        #timeout server  50000
> 
> and restart the haproxy service for the changes to take effect.
> 
> Again, many thanks Remi, greatly appreciated. :)
> 
> -ip-
> 
> 
> On Sun, May 1, 2016 at 4:30 AM, Remi Bergsma <RB...@schubergphilis.com>
> wrote:
> 
>> Hi,
>> 
>> You may want to check if HAproxy keeps the connection open long enough.
>> The system vms send traffic every minute or so and you want haproxy to keep
>> the connection open longer than that. If haproxy is set to close idle
>> connections after say 30sec then this will result in flapping connections.
>> 
>> Regards, Remi
>> 
>> Sent from my iPhone
>> 
>>> On 30 Apr 2016, at 22:00, Indra Pramana <in...@sg.or.id> wrote:
>>> 
>>> Dear all,
>>> 
>>> We are running CloudStack 4.2.0 with KVM hypervisor and Ceph RBD storage.
>>> We implemented secondary CloudStack management server and haproxy load
>>> balancer, and tonight we changed our configuration so that the CloudStack
>>> agents will be connecting to the LB IP rather than the CS mgmt server
>>> directly.
>>> 
>>> However, we noted that the agent will be regularly disconnected every 2-3
>>> minutes. Here are the excerpts on the agent.log:
>>> 
>>> ====
>>> 2016-05-01 01:30:10,982 DEBUG [utils.nio.NioConnection]
>>> (Agent-Selector:null) Location 1: Socket
>>> Socket[addr=/X.X.X.8,port=8250,localport=50613] closed on read.  Pro
>>> bably -1 returned: Connection closed with -1 on reading size.
>>> 2016-05-01 01:30:10,983 DEBUG [utils.nio.NioConnection]
>>> (Agent-Selector:null) Closing socket
>>> Socket[addr=/X.X.X.8,port=8250,localport=50613]
>>> 2016-05-01 01:30:10,983 DEBUG [cloud.agent.Agent] (Agent-Handler-3:null)
>>> Clearing watch list: 2
>>> 2016-05-01 01:30:15,984 INFO  [cloud.agent.Agent] (Agent-Handler-3:null)
>>> Lost connection to the server. Dealing with the remaining commands...
>>> 2016-05-01 01:30:20,985 INFO  [cloud.agent.Agent] (Agent-Handler-3:null)
>>> Reconnecting...
>>> 2016-05-01 01:30:20,986 INFO  [utils.nio.NioClient] (Agent-Selector:null)
>>> Connecting to X.X.X.8:8250
>>> 2016-05-01 01:30:21,101 INFO  [utils.nio.NioClient] (Agent-Selector:null)
>>> SSL: Handshake done
>>> 2016-05-01 01:30:21,101 INFO  [utils.nio.NioClient] (Agent-Selector:null)
>>> Connected to X.X.X.8:8250
>>> 2016-05-01 01:30:21,133 DEBUG [kvm.resource.LibvirtCapXMLParser]
>>> (Agent-Handler-1:null) Found /usr/bin/kvm as a suiteable emulator
>>> 2016-05-01 01:30:21,134 DEBUG [kvm.resource.LibvirtComputingResource]
>>> (Agent-Handler-1:null) Executing: /bin/bash -c qemu-img --help|grep
>> convert
>>> 2016-05-01 01:30:21,152 DEBUG [kvm.resource.LibvirtComputingResource]
>>> (Agent-Handler-1:null) Execution is successful.
>>> 2016-05-01 01:30:21,152 DEBUG [kvm.resource.LibvirtComputingResource]
>>> (Agent-Handler-1:null)   convert [-c] [-p] [-q] [-n] [-f fmt] [-t cache]
>>> [-T src_cache] [-O output
>>> _fmt] [-o options] [-s snapshot_id_or_name] [-l snapshot_param] [-S
>>> sparse_size] filename [filename2 [...]] output_filename
>>>   options are: 'none', 'writeback' (default, except for convert),
>>> 'writethrough',
>>>   'directsync' and 'unsafe' (default for convert)
>>> ====
>>> 
>>> and then it will reconnected again, and then got disconnected again, etc.
>>> It will continue on that loop.
>>> 
>>> haproxy.cfg configuration for the NIC facing the hypervisors:
>>> 
>>> ====
>>> listen cloudstack_systemvm_8250
>>> bind X.X.X.8:8250
>>> mode tcp
>>> option tcplog
>>> balance source
>>> server management-server-01.xxx.com X.X.X.3:8250 maxconn 32 check
>>> server management-server-02.xxx.com X.X.X.6:8250 maxconn 32 check
>>> ====
>>> 
>>> Note that .3 and .6 are the first and second CloudStack management
>> servers
>>> respectively, while .8 is the IP of the load balancer. We are using one
>> LB
>>> at the moment.
>>> 
>>> Nothing much is found on the haproxy.log, see below.
>>> 
>>> ====
>>> May  1 01:14:41 cs-haproxy-02 haproxy[923]: X.X.X.28:50401
>>> [01/May/2016:01:12:50.803] cloudstack_systemvm_8250
>>> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/110340 8584 cD
>>> 0/0/0/0/0 0/0
>>> May  1 01:15:46 cs-haproxy-02 haproxy[923]: X.X.X.28:50402
>>> [01/May/2016:01:14:51.150] cloudstack_systemvm_8250
>>> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/54920 8234 cD
>>> 0/0/0/0/0 0/0
>>> May  1 01:16:47 cs-haproxy-02 haproxy[923]: X.X.X.28:50403
>>> [01/May/2016:01:15:56.075] cloudstack_systemvm_8250
>>> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/51344 7868 cD
>>> 0/0/0/0/0 0/0
>>> May  1 01:17:48 cs-haproxy-02 haproxy[923]: X.X.X.28:50404
>>> [01/May/2016:01:16:57.426] cloudstack_systemvm_8250
>>> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50854 7630 cD
>>> 0/0/0/0/0 0/0
>>> May  1 01:18:49 cs-haproxy-02 haproxy[923]: X.X.X.28:50405
>>> [01/May/2016:01:17:58.285] cloudstack_systemvm_8250
>>> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50955 7630 cD
>>> 0/0/0/0/0 0/0
>>> May  1 01:24:49 cs-haproxy-02 haproxy[923]: X.X.X.28:50406
>>> [01/May/2016:01:18:59.245] cloudstack_systemvm_8250
>>> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/350361 14638
>> cD
>>> 0/0/0/0/0 0/0
>>> May  1 01:28:00 cs-haproxy-02 haproxy[923]: X.X.X.28:50571
>>> [01/May/2016:01:27:09.638] cloudstack_systemvm_8250
>>> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50602 2852 cD
>>> 0/0/0/0/0 0/0
>>> May  1 01:30:11 cs-haproxy-02 haproxy[923]: X.X.X.28:50613
>>> [01/May/2016:01:29:20.260] cloudstack_systemvm_8250
>>> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50876 7630 cD
>>> 0/0/0/0/0 0/0
>>> May  1 01:32:11 cs-haproxy-02 haproxy[923]: X.X.X.28:50614
>>> [01/May/2016:01:30:21.142] cloudstack_systemvm_8250
>>> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/110308 8870 cD
>>> 0/0/0/0/0 0/0
>>> ====
>>> 
>>> Note that .28 is the IP address of the hypervisor I tested to connect to
>>> the LB IP. Did I missed out anything on the haproxy configuration? Any
>>> advice is greatly appreciated.
>>> 
>>> Looking forward to your reply, thank you.
>>> 
>>> Cheers.
>> 

Re: regular disconnection every 2-3 mins on haproxy cloudstack mgmt server LB implementation

Posted by Indra Pramana <in...@sg.or.id>.
Hi Remi,

Many thanks for your tips! You are right indeed, by default haproxy has
timeout set to 50 seconds (or 50,000ms). I changed it to 120 seconds (2
minutes) and have monitored the agent connection and it's no longer
flapping. Monitoring now and will let you know if there are any further
issues.

On /etc/haproxy/haproxy.cfg, modify this under defaults section:

        timeout client  120000
        timeout server  120000
        #timeout client  50000
        #timeout server  50000

and restart the haproxy service for the changes to take effect.

Again, many thanks Remi, greatly appreciated. :)

-ip-


On Sun, May 1, 2016 at 4:30 AM, Remi Bergsma <RB...@schubergphilis.com>
wrote:

> Hi,
>
> You may want to check if HAproxy keeps the connection open long enough.
> The system vms send traffic every minute or so and you want haproxy to keep
> the connection open longer than that. If haproxy is set to close idle
> connections after say 30sec then this will result in flapping connections.
>
> Regards, Remi
>
> Sent from my iPhone
>
> > On 30 Apr 2016, at 22:00, Indra Pramana <in...@sg.or.id> wrote:
> >
> > Dear all,
> >
> > We are running CloudStack 4.2.0 with KVM hypervisor and Ceph RBD storage.
> > We implemented secondary CloudStack management server and haproxy load
> > balancer, and tonight we changed our configuration so that the CloudStack
> > agents will be connecting to the LB IP rather than the CS mgmt server
> > directly.
> >
> > However, we noted that the agent will be regularly disconnected every 2-3
> > minutes. Here are the excerpts on the agent.log:
> >
> > ====
> > 2016-05-01 01:30:10,982 DEBUG [utils.nio.NioConnection]
> > (Agent-Selector:null) Location 1: Socket
> > Socket[addr=/X.X.X.8,port=8250,localport=50613] closed on read.  Pro
> > bably -1 returned: Connection closed with -1 on reading size.
> > 2016-05-01 01:30:10,983 DEBUG [utils.nio.NioConnection]
> > (Agent-Selector:null) Closing socket
> > Socket[addr=/X.X.X.8,port=8250,localport=50613]
> > 2016-05-01 01:30:10,983 DEBUG [cloud.agent.Agent] (Agent-Handler-3:null)
> > Clearing watch list: 2
> > 2016-05-01 01:30:15,984 INFO  [cloud.agent.Agent] (Agent-Handler-3:null)
> > Lost connection to the server. Dealing with the remaining commands...
> > 2016-05-01 01:30:20,985 INFO  [cloud.agent.Agent] (Agent-Handler-3:null)
> > Reconnecting...
> > 2016-05-01 01:30:20,986 INFO  [utils.nio.NioClient] (Agent-Selector:null)
> > Connecting to X.X.X.8:8250
> > 2016-05-01 01:30:21,101 INFO  [utils.nio.NioClient] (Agent-Selector:null)
> > SSL: Handshake done
> > 2016-05-01 01:30:21,101 INFO  [utils.nio.NioClient] (Agent-Selector:null)
> > Connected to X.X.X.8:8250
> > 2016-05-01 01:30:21,133 DEBUG [kvm.resource.LibvirtCapXMLParser]
> > (Agent-Handler-1:null) Found /usr/bin/kvm as a suiteable emulator
> > 2016-05-01 01:30:21,134 DEBUG [kvm.resource.LibvirtComputingResource]
> > (Agent-Handler-1:null) Executing: /bin/bash -c qemu-img --help|grep
> convert
> > 2016-05-01 01:30:21,152 DEBUG [kvm.resource.LibvirtComputingResource]
> > (Agent-Handler-1:null) Execution is successful.
> > 2016-05-01 01:30:21,152 DEBUG [kvm.resource.LibvirtComputingResource]
> > (Agent-Handler-1:null)   convert [-c] [-p] [-q] [-n] [-f fmt] [-t cache]
> > [-T src_cache] [-O output
> > _fmt] [-o options] [-s snapshot_id_or_name] [-l snapshot_param] [-S
> > sparse_size] filename [filename2 [...]] output_filename
> >    options are: 'none', 'writeback' (default, except for convert),
> > 'writethrough',
> >    'directsync' and 'unsafe' (default for convert)
> > ====
> >
> > and then it will reconnected again, and then got disconnected again, etc.
> > It will continue on that loop.
> >
> > haproxy.cfg configuration for the NIC facing the hypervisors:
> >
> > ====
> > listen cloudstack_systemvm_8250
> > bind X.X.X.8:8250
> > mode tcp
> > option tcplog
> > balance source
> > server management-server-01.xxx.com X.X.X.3:8250 maxconn 32 check
> > server management-server-02.xxx.com X.X.X.6:8250 maxconn 32 check
> > ====
> >
> > Note that .3 and .6 are the first and second CloudStack management
> servers
> > respectively, while .8 is the IP of the load balancer. We are using one
> LB
> > at the moment.
> >
> > Nothing much is found on the haproxy.log, see below.
> >
> > ====
> > May  1 01:14:41 cs-haproxy-02 haproxy[923]: X.X.X.28:50401
> > [01/May/2016:01:12:50.803] cloudstack_systemvm_8250
> > cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/110340 8584 cD
> > 0/0/0/0/0 0/0
> > May  1 01:15:46 cs-haproxy-02 haproxy[923]: X.X.X.28:50402
> > [01/May/2016:01:14:51.150] cloudstack_systemvm_8250
> > cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/54920 8234 cD
> > 0/0/0/0/0 0/0
> > May  1 01:16:47 cs-haproxy-02 haproxy[923]: X.X.X.28:50403
> > [01/May/2016:01:15:56.075] cloudstack_systemvm_8250
> > cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/51344 7868 cD
> > 0/0/0/0/0 0/0
> > May  1 01:17:48 cs-haproxy-02 haproxy[923]: X.X.X.28:50404
> > [01/May/2016:01:16:57.426] cloudstack_systemvm_8250
> > cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50854 7630 cD
> > 0/0/0/0/0 0/0
> > May  1 01:18:49 cs-haproxy-02 haproxy[923]: X.X.X.28:50405
> > [01/May/2016:01:17:58.285] cloudstack_systemvm_8250
> > cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50955 7630 cD
> > 0/0/0/0/0 0/0
> > May  1 01:24:49 cs-haproxy-02 haproxy[923]: X.X.X.28:50406
> > [01/May/2016:01:18:59.245] cloudstack_systemvm_8250
> > cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/350361 14638
> cD
> > 0/0/0/0/0 0/0
> > May  1 01:28:00 cs-haproxy-02 haproxy[923]: X.X.X.28:50571
> > [01/May/2016:01:27:09.638] cloudstack_systemvm_8250
> > cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50602 2852 cD
> > 0/0/0/0/0 0/0
> > May  1 01:30:11 cs-haproxy-02 haproxy[923]: X.X.X.28:50613
> > [01/May/2016:01:29:20.260] cloudstack_systemvm_8250
> > cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50876 7630 cD
> > 0/0/0/0/0 0/0
> > May  1 01:32:11 cs-haproxy-02 haproxy[923]: X.X.X.28:50614
> > [01/May/2016:01:30:21.142] cloudstack_systemvm_8250
> > cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/110308 8870 cD
> > 0/0/0/0/0 0/0
> > ====
> >
> > Note that .28 is the IP address of the hypervisor I tested to connect to
> > the LB IP. Did I missed out anything on the haproxy configuration? Any
> > advice is greatly appreciated.
> >
> > Looking forward to your reply, thank you.
> >
> > Cheers.
>

Re: regular disconnection every 2-3 mins on haproxy cloudstack mgmt server LB implementation

Posted by Remi Bergsma <RB...@schubergphilis.com>.
Hi,

You may want to check if HAproxy keeps the connection open long enough. The system vms send traffic every minute or so and you want haproxy to keep the connection open longer than that. If haproxy is set to close idle connections after say 30sec then this will result in flapping connections. 

Regards, Remi 

Sent from my iPhone

> On 30 Apr 2016, at 22:00, Indra Pramana <in...@sg.or.id> wrote:
> 
> Dear all,
> 
> We are running CloudStack 4.2.0 with KVM hypervisor and Ceph RBD storage.
> We implemented secondary CloudStack management server and haproxy load
> balancer, and tonight we changed our configuration so that the CloudStack
> agents will be connecting to the LB IP rather than the CS mgmt server
> directly.
> 
> However, we noted that the agent will be regularly disconnected every 2-3
> minutes. Here are the excerpts on the agent.log:
> 
> ====
> 2016-05-01 01:30:10,982 DEBUG [utils.nio.NioConnection]
> (Agent-Selector:null) Location 1: Socket
> Socket[addr=/X.X.X.8,port=8250,localport=50613] closed on read.  Pro
> bably -1 returned: Connection closed with -1 on reading size.
> 2016-05-01 01:30:10,983 DEBUG [utils.nio.NioConnection]
> (Agent-Selector:null) Closing socket
> Socket[addr=/X.X.X.8,port=8250,localport=50613]
> 2016-05-01 01:30:10,983 DEBUG [cloud.agent.Agent] (Agent-Handler-3:null)
> Clearing watch list: 2
> 2016-05-01 01:30:15,984 INFO  [cloud.agent.Agent] (Agent-Handler-3:null)
> Lost connection to the server. Dealing with the remaining commands...
> 2016-05-01 01:30:20,985 INFO  [cloud.agent.Agent] (Agent-Handler-3:null)
> Reconnecting...
> 2016-05-01 01:30:20,986 INFO  [utils.nio.NioClient] (Agent-Selector:null)
> Connecting to X.X.X.8:8250
> 2016-05-01 01:30:21,101 INFO  [utils.nio.NioClient] (Agent-Selector:null)
> SSL: Handshake done
> 2016-05-01 01:30:21,101 INFO  [utils.nio.NioClient] (Agent-Selector:null)
> Connected to X.X.X.8:8250
> 2016-05-01 01:30:21,133 DEBUG [kvm.resource.LibvirtCapXMLParser]
> (Agent-Handler-1:null) Found /usr/bin/kvm as a suiteable emulator
> 2016-05-01 01:30:21,134 DEBUG [kvm.resource.LibvirtComputingResource]
> (Agent-Handler-1:null) Executing: /bin/bash -c qemu-img --help|grep convert
> 2016-05-01 01:30:21,152 DEBUG [kvm.resource.LibvirtComputingResource]
> (Agent-Handler-1:null) Execution is successful.
> 2016-05-01 01:30:21,152 DEBUG [kvm.resource.LibvirtComputingResource]
> (Agent-Handler-1:null)   convert [-c] [-p] [-q] [-n] [-f fmt] [-t cache]
> [-T src_cache] [-O output
> _fmt] [-o options] [-s snapshot_id_or_name] [-l snapshot_param] [-S
> sparse_size] filename [filename2 [...]] output_filename
>    options are: 'none', 'writeback' (default, except for convert),
> 'writethrough',
>    'directsync' and 'unsafe' (default for convert)
> ====
> 
> and then it will reconnected again, and then got disconnected again, etc.
> It will continue on that loop.
> 
> haproxy.cfg configuration for the NIC facing the hypervisors:
> 
> ====
> listen cloudstack_systemvm_8250
> bind X.X.X.8:8250
> mode tcp
> option tcplog
> balance source
> server management-server-01.xxx.com X.X.X.3:8250 maxconn 32 check
> server management-server-02.xxx.com X.X.X.6:8250 maxconn 32 check
> ====
> 
> Note that .3 and .6 are the first and second CloudStack management servers
> respectively, while .8 is the IP of the load balancer. We are using one LB
> at the moment.
> 
> Nothing much is found on the haproxy.log, see below.
> 
> ====
> May  1 01:14:41 cs-haproxy-02 haproxy[923]: X.X.X.28:50401
> [01/May/2016:01:12:50.803] cloudstack_systemvm_8250
> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/110340 8584 cD
> 0/0/0/0/0 0/0
> May  1 01:15:46 cs-haproxy-02 haproxy[923]: X.X.X.28:50402
> [01/May/2016:01:14:51.150] cloudstack_systemvm_8250
> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/54920 8234 cD
> 0/0/0/0/0 0/0
> May  1 01:16:47 cs-haproxy-02 haproxy[923]: X.X.X.28:50403
> [01/May/2016:01:15:56.075] cloudstack_systemvm_8250
> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/51344 7868 cD
> 0/0/0/0/0 0/0
> May  1 01:17:48 cs-haproxy-02 haproxy[923]: X.X.X.28:50404
> [01/May/2016:01:16:57.426] cloudstack_systemvm_8250
> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50854 7630 cD
> 0/0/0/0/0 0/0
> May  1 01:18:49 cs-haproxy-02 haproxy[923]: X.X.X.28:50405
> [01/May/2016:01:17:58.285] cloudstack_systemvm_8250
> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50955 7630 cD
> 0/0/0/0/0 0/0
> May  1 01:24:49 cs-haproxy-02 haproxy[923]: X.X.X.28:50406
> [01/May/2016:01:18:59.245] cloudstack_systemvm_8250
> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/350361 14638 cD
> 0/0/0/0/0 0/0
> May  1 01:28:00 cs-haproxy-02 haproxy[923]: X.X.X.28:50571
> [01/May/2016:01:27:09.638] cloudstack_systemvm_8250
> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50602 2852 cD
> 0/0/0/0/0 0/0
> May  1 01:30:11 cs-haproxy-02 haproxy[923]: X.X.X.28:50613
> [01/May/2016:01:29:20.260] cloudstack_systemvm_8250
> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/50876 7630 cD
> 0/0/0/0/0 0/0
> May  1 01:32:11 cs-haproxy-02 haproxy[923]: X.X.X.28:50614
> [01/May/2016:01:30:21.142] cloudstack_systemvm_8250
> cloudstack_systemvm_8250/management-server-01.xxx.com 1/0/110308 8870 cD
> 0/0/0/0/0 0/0
> ====
> 
> Note that .28 is the IP address of the hypervisor I tested to connect to
> the LB IP. Did I missed out anything on the haproxy configuration? Any
> advice is greatly appreciated.
> 
> Looking forward to your reply, thank you.
> 
> Cheers.