Mailing List Archive: OpenStack: Operators

Re: [openstack-operators] Neutron HA

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rpodolyaka at mirantis

Jul 19, 2013, 2:59 AM

Post #1 of 6 (101 views)
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Re: [openstack-operators] Neutron HA

Hi all,

Indeed, Neutron doesn't provide an HA solution out-of-box. I would say
that, agents scheduling described in [1] is just the first step on a way to
HA.

Nevertheless, there are a few ways of providing HA for different parts of
Neutron requiring some additional efforts:

1. DHCP-agent. Neutron networks can be scheduled to a few DHCP-agents
running on different nodes, and thus providing HA for DHCP in Active/Active
mode.

2. L3-agent. Neutron routers can be scheduled to a few L3-agents, but only
one of them can be active at the time. Should an L3-agent hosting a router
fail, it's up to you to reschedule the router. Though, an Active/Active HA
solution was proposed recently [2].

3. L2-agent. An agent of this type is run on every node of a cluster. I'm
not sure you can run a multiple instances of it on one node (as it performs
configuration of network interfaces/etc, so this would eventually lead to
race-conditions). So this is similar to a failure of nova-compute daemon or
a physical node.

Thanks,
Roman

[1]
http://www.mirantis.com/blog/a-new-agent-management-approach-in-quantum-for-openstack-grizzly/
[2]
http://telekomcloud.github.io/2013/06/10/openstack-networking-high-availability.html

jacobgodin at gmail

Jul 19, 2013, 5:17 AM

Post #2 of 6 (97 views)
Permalink

Re: [openstack-operators] Neutron HA [In reply to]

Hi Roman,

Thanks for your detailed response.

1. Is there anyway to have Neutron schedule DHCP on all DHCP agents by
default? We are running a multi-tenant setup, and most of our users will be
using Horizon to deploy their instances/networking. It would be great to
have an option in the Neutron config to automatically push to all agents.

2. Do you have a blueprint to follow for this? Would be great to see!

3. So if we spin up another "network node" with the OVS agent running on
it, it should automatically create the L2 networking there as well?

Thanks!

On Fri, Jul 19, 2013 at 6:59 AM, Roman Podolyaka <rpodolyaka [at] mirantis>wrote:

> Hi all,
>
> Indeed, Neutron doesn't provide an HA solution out-of-box. I would say
> that, agents scheduling described in [1] is just the first step on a way to
> HA.
>
> Nevertheless, there are a few ways of providing HA for different parts of
> Neutron requiring some additional efforts:
>
> 1. DHCP-agent. Neutron networks can be scheduled to a few DHCP-agents
> running on different nodes, and thus providing HA for DHCP in Active/Active
> mode.
>
> 2. L3-agent. Neutron routers can be scheduled to a few L3-agents, but only
> one of them can be active at the time. Should an L3-agent hosting a router
> fail, it's up to you to reschedule the router. Though, an Active/Active HA
> solution was proposed recently [2].
>
> 3. L2-agent. An agent of this type is run on every node of a cluster. I'm
> not sure you can run a multiple instances of it on one node (as it performs
> configuration of network interfaces/etc, so this would eventually lead to
> race-conditions). So this is similar to a failure of nova-compute daemon or
> a physical node.
>
> Thanks,
> Roman
>
> [1]
> http://www.mirantis.com/blog/a-new-agent-management-approach-in-quantum-for-openstack-grizzly/
> [2]
> http://telekomcloud.github.io/2013/06/10/openstack-networking-high-availability.html
>
> _______________________________________________
> OpenStack-operators mailing list
> OpenStack-operators [at] lists
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
>
>

rpodolyaka at mirantis

Jul 19, 2013, 6:07 AM

Post #3 of 6 (97 views)
Permalink

Re: [openstack-operators] Neutron HA [In reply to]

Hi Jacob, all

1. When a new Neutron network is created, it is automatically scheduled to
one of DHCP-agents running in a cluster (actually, it's done lazily, when
the first port on this network is created, but that's an implementation
detail). Though, you have to manually schedule it to additional DHCP-agents
to provide HA. I haven't seen any BPs adding such an option, but I agree,
that it would be useful to have one.

2. Not sure we have one :( The solution from TelekomCloud guys seems to be
the only way to go to provide HA for L3 agents in Active/Active mode
currently.

3. Every network or compute node in a cluster runs an L2-agent, which
allows one to create L2 tenant networks and plug VMs/routers/DHCP-servers
into network ports (the underlying implementation depends on the core
plugin you use, e.g. OVS can use VLANs or GRE tunnels to provide tenant
isolation). So L2 networking is ready to use when you've started an
L2-agent and provided it with a correct configuration file.

Thanks,
Roman

simon.pasquier at bull

Jul 19, 2013, 6:35 AM

Post #4 of 6 (97 views)
Permalink

Re: [openstack-operators] Neutron HA [In reply to]

Le 19/07/2013 15:07, Roman Podolyaka a �crit :
> Hi Jacob, all
>
> 1. When a new Neutron network is created, it is automatically
> scheduled to one of DHCP-agents running in a cluster (actually, it's
> done lazily, when the first port on this network is created, but
> that's an implementation detail). Though, you have to manually
> schedule it to additional DHCP-agents to provide HA. I haven't seen
> any BPs adding such an option, but I agree, that it would be useful to
> have one.

It already exists in Havana by setting the dhcp_agents_per_network
parameter in neutron.conf .
Check this commit for details:
https://github.com/openstack/neutron/commit/c95e58b70796eae6bbc8bac283f81df9aa1d1894

>
> 2. Not sure we have one :( The solution from TelekomCloud guys seems
> to be the only way to go to provide HA for L3 agents in Active/Active
> mode currently.
>
> 3. Every network or compute node in a cluster runs an L2-agent, which
> allows one to create L2 tenant networks and plug
> VMs/routers/DHCP-servers into network ports (the underlying
> implementation depends on the core plugin you use, e.g. OVS can use
> VLANs or GRE tunnels to provide tenant isolation). So L2 networking is
> ready to use when you've started an L2-agent and provided it with a
> correct configuration file.
>
> Thanks,
> Roman
>
>
> _______________________________________________
> OpenStack-operators mailing list
> OpenStack-operators [at] lists
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators

--
Simon Pasquier
Software Engineer
Bull, Architect of an Open World
Phone: + 33 4 76 29 71 49
http://www.bull.com

rpodolyaka at mirantis

Jul 19, 2013, 7:09 AM

Post #5 of 6 (96 views)
Permalink

Re: [openstack-operators] Neutron HA [In reply to]

Hi all,

Thanks, Akihiro and Simon! I didn't know we had such option.

>> Regarding 1, the configuration option "dhcp_agents_per_network" is
introduced. This options specifies the number of DHCP agents scheduled to
host a network.
>> If you set this option to the number of dhcp agents, you can do this.

>> It already exists in Havana by setting the dhcp_agents_per_network
parameter in neutron.conf .
>> Check this commit for details:
https://github.com/openstack/neutron/commit/c95e58b70796eae6bbc8bac283f81df9aa1d1894

On Fri, Jul 19, 2013 at 4:35 PM, Simon Pasquier <simon.pasquier [at] bull>wrote:

> Le 19/07/2013 15:07, Roman Podolyaka a �crit :
>
> Hi Jacob, all
>
> 1. When a new Neutron network is created, it is automatically scheduled
> to one of DHCP-agents running in a cluster (actually, it's done lazily,
> when the first port on this network is created, but that's an
> implementation detail). Though, you have to manually schedule it to
> additional DHCP-agents to provide HA. I haven't seen any BPs adding such an
> option, but I agree, that it would be useful to have one.
>
>
> It already exists in Havana by setting the dhcp_agents_per_network
> parameter in neutron.conf .
> Check this commit for details:
>
> https://github.com/openstack/neutron/commit/c95e58b70796eae6bbc8bac283f81df9aa1d1894
>
>
> 2. Not sure we have one :( The solution from TelekomCloud guys seems to
> be the only way to go to provide HA for L3 agents in Active/Active mode
> currently.
>
> 3. Every network or compute node in a cluster runs an L2-agent, which
> allows one to create L2 tenant networks and plug VMs/routers/DHCP-servers
> into network ports (the underlying implementation depends on the core
> plugin you use, e.g. OVS can use VLANs or GRE tunnels to provide tenant
> isolation). So L2 networking is ready to use when you've started an
> L2-agent and provided it with a correct configuration file.
>
> Thanks,
> Roman
>
>
> _______________________________________________
> OpenStack-operators mailing listOpenStack-operators [at] listshttp://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
>
>
>
> --
> Simon Pasquier
> Software Engineer
> Bull, Architect of an Open World
> Phone: + 33 4 76 29 71 49http://www.bull.com
>
>
> _______________________________________________
> OpenStack-operators mailing list
> OpenStack-operators [at] lists
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
>
>

jacobgodin at gmail

Jul 23, 2013, 4:54 AM

Post #6 of 6 (84 views)
Permalink

Re: [openstack-operators] Neutron HA [In reply to]

Not specifically to Neutron HA, but a great video none the less:
http://www.youtube.com/watch?v=N9mPepfxm-4

On Fri, Jul 19, 2013 at 11:09 AM, Roman Podolyaka
<rpodolyaka [at] mirantis>wrote:

> Hi all,
>
> Thanks, Akihiro and Simon! I didn't know we had such option.
>
> introduced. This options specifies the number of DHCP agents scheduled to
> host a network.
>
> parameter in neutron.conf .
> https://github.com/openstack/neutron/commit/c95e58b70796eae6bbc8bac283f81df9aa1d1894
>
>
> On Fri, Jul 19, 2013 at 4:35 PM, Simon Pasquier <simon.pasquier [at] bull>wrote:
>
>> Le 19/07/2013 15:07, Roman Podolyaka a �crit :
>>
>> Hi Jacob, all
>>
>> 1. When a new Neutron network is created, it is automatically scheduled
>> to one of DHCP-agents running in a cluster (actually, it's done lazily,
>> when the first port on this network is created, but that's an
>> implementation detail). Though, you have to manually schedule it to
>> additional DHCP-agents to provide HA. I haven't seen any BPs adding such an
>> option, but I agree, that it would be useful to have one.
>>
>>
>> It already exists in Havana by setting the dhcp_agents_per_network
>> parameter in neutron.conf .
>> Check this commit for details:
>>
>> https://github.com/openstack/neutron/commit/c95e58b70796eae6bbc8bac283f81df9aa1d1894
>>
>>
>> 2. Not sure we have one :( The solution from TelekomCloud guys seems to
>> be the only way to go to provide HA for L3 agents in Active/Active mode
>> currently.
>>
>> 3. Every network or compute node in a cluster runs an L2-agent, which
>> allows one to create L2 tenant networks and plug VMs/routers/DHCP-servers
>> into network ports (the underlying implementation depends on the core
>> plugin you use, e.g. OVS can use VLANs or GRE tunnels to provide tenant
>> isolation). So L2 networking is ready to use when you've started an
>> L2-agent and provided it with a correct configuration file.
>>
>> Thanks,
>> Roman
>>
>>
>> _______________________________________________
>> OpenStack-operators mailing listOpenStack-operators [at] listshttp://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
>>
>>
>>
>> --
>> Simon Pasquier
>> Software Engineer
>> Bull, Architect of an Open World
>> Phone: + 33 4 76 29 71 49http://www.bull.com
>>
>>
>> _______________________________________________
>> OpenStack-operators mailing list
>> OpenStack-operators [at] lists
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
>>
>>
>
> _______________________________________________
> OpenStack-operators mailing list
> OpenStack-operators [at] lists
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
>
>

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