Date: Tue, 21 Feb 2012 08:43:04 +0100 From: Damien Fleuriot <ml@my.gd> To: peter knezel <peter.knezel@gmail.com> Cc: "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org> Subject: Re: From analysis of a simple ifstated.conf to more compex example Message-ID: <DAC13949-407E-400A-B5BD-489CE800A380@my.gd> In-Reply-To: <CAAwfu_=OPqKpPxRvmf3gByq3Zqdm3DY52KvEA%2BNwOXQxJnkNGg@mail.gmail.com> References: <CAAwfu_n%2BVjgeihzWRa1F6v6PhCA943sFHR7eFxA1Ycc8NbjXpQ@mail.gmail.com> <4F314AFB.8080901@my.gd> <CAAwfu_kfj2mqT9qVSh2_9LpfcvOrxBJiwNRi_x79VcjGQLwGqw@mail.gmail.com> <4F3BEA73.9060005@my.gd> <CAAwfu_=5-t0=C2_2ZeK5cf3N-e5_%2BiZPGLPk9S-Tks78sKpVYA@mail.gmail.com> <4F3CC11D.1080105@my.gd> <CAAwfu_=OPqKpPxRvmf3gByq3Zqdm3DY52KvEA%2BNwOXQxJnkNGg@mail.gmail.com>
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To be honest, I'm not sure it's a good idea to use different *interfaces*.
Why don't you set multiple IPs on a single carp interface instead ?
On 21 Feb 2012, at 08:29, peter knezel <peter.knezel@gmail.com> wrote:
> Hello Damien,
>=20
> preemption is set on both systems, so when master server goes down or
> any CARP interface on master
> goes down, slave becomes master (but only on the CARP interface if
> only that went down).
>=20
> Can you have a look at my previous question??:
> if the different carp interfaces
> are used for different purpose (ftp, tftp, scp), is it a good idea to
> put down all of them, if they are able to serve their purpose?
>=20
>=20
> Thanks and kind regards,
>=20
> Peter
>=20
> On 16/02/2012, Damien Fleuriot <ml@my.gd> wrote:
>> Preemption is used to ensure that, if a CARP interface goes down on host
>> A, host B will then assume mastership for all interfaces.
>>=20
>> It prevents the nasty situation where you'd have, for example:
>>=20
>> Public IP: master on host A
>> Private IP: master on host B
>>=20
>> servers behind firewalls hosts A and B:
>> - traffic arrives on host A which creates a PF state
>> - servers reply via their default gateway, the CARP IP now master on host=
B
>>=20
>> Host B doesn't have a state for the traffic, drops it.
>>=20
>>=20
>> To enable preemption you need to run sysctl net.inet.carp.preempt=3D1 and=
>> add the corresponding line to your sysctls file in etc.
>>=20
>>=20
>> On 2/15/12 7:04 PM, peter knezel wrote:
>>> Well,
>>>=20
>>> I am not fully familiar with CARP, but if the different carp interfaces
>>> are used for different purpose (ftp, tftp, scp), is it a good idea to
>>> put down all of them, if they are able to serve their purpose?
>>>=20
>>> BTW, what is CARP preemption and how is it possible to enable it?
>>>=20
>>> Kind regards,
>>>=20
>>> Peter
>>>=20
>>> On 15 February 2012 18:25, Damien Fleuriot <ml@my.gd <mailto:ml@my.gd>>
>>> wrote:
>>>=20
>>> Sorry about the late reply, didn't see yours.
>>>=20
>>> What about enabling CARP preemption to ensure that when a carp
>>> interface
>>> goes down, the whole set does ?
>>>=20
>>>=20
>>> On 2/7/12 9:13 PM, peter knezel wrote:
>>>> Hello Damien,
>>>>=20
>>>> I did read your example but cannot get idea from it.
>>>> For three interfaces you have much more possibilities.
>>>>=20
>>>> Imagine you start the server from uuu state which is equal to
>>>> net =3D '( "ifconfig -a -u |grep carp0 > /dev/null" every 3 &&
>>> "ifconfig -a -u
>>>> |grep carp1 > /dev/null" every 3 && "ifconfig -a -u |grep carp2 >
>>> /dev/null"
>>>> every 3)'
>>>>=20
>>>> Now you put down one carp interface - so system is in state :
>>>> *state one:*
>>>> (duu) || (udu) || (uud) <----which is same as !$net
>>>> run script1.sh
>>>> go to twoff
>>>>=20
>>>> now imagine, you put down any other carp interface:
>>>> *state twoff: *
>>>> (dud) || (ddu) || (udd)
>>>> run script2.sh
>>>> go to two
>>>>=20
>>>> *state two: *
>>>> put all interfaces up
>>>> run script3.sh
>>>> go to state one
>>>>=20
>>>> it means, this is one of the possibilities system can behave (this
>>>> situation does not describe all possible states - I have taken this
>>>> special example.)
>>>>=20
>>>> Now if you want to put up after putting down one carp interface, you
>>>> fail since it is in state twoff.
>>>> Only of you put down second carp interface it goes to state two and
>>> if
>>>> you put both up, it will go to state one.
>>>>=20
>>>> This is where my ifstated.conf fails to work.
>>>>=20
>>>> Kind regards,
>>>>=20
>>>> Peter Knezel
>>>>=20
>>>>=20
>>>> On 7 February 2012 17:02, Damien Fleuriot <ml@my.gd
>>> <mailto:ml@my.gd> <mailto:ml@my.gd <mailto:ml@my.gd>>>
>>>> wrote:
>>>>=20
>>>> On 2/7/12 3:36 PM, peter knezel wrote:
>>>>> Hello all,
>>>>>=20
>>>>> I would like to ask somebody to explain me how the ifstated
>>> works
>>>> according to
>>>>> the following configuration file.
>>>>> I have three virtual carp interfaces carp0,carp1 and carp2.
>>>>>=20
>>>>> I try to understand the following setting:
>>>>> The server is in state one (all carp interfaces are up) and
>>> if there
>>>>> is carp down of any:
>>>>> one (carp0 or carp1 or carp2),
>>>>> two ([carp0 and carp1] or [carp0 and carp2] or [carp1 and
>>> carp2]),
>>>>> three interfaces (carp 0 and carp1 and carp2), server
>>>>> runs the script testdown.sh and put the server into state two.
>>>>> If all carp interfaces are up, the server runs the testup.sh
>>> and set
>>>>> the state to one.
>>>>>=20
>>>>=20
>>>> That is my understanding.
>>>>=20
>>>>=20
>>>>> Is it the way the system works?
>>>>> Or am I wrong?
>>>>>=20
>>>>> =3D=3D=3D
>>>>> init-state one
>>>>>=20
>>>>> net =3D '( "ifconfig -a -u |grep carp0 > /dev/null" every 3 &&
>>>> "ifconfig -a -u
>>>>> |grep carp1 > /dev/null" every 3 && "ifconfig -a -u |grep
>>> carp2 >
>>>> /dev/null"
>>>>> every 3)'
>>>>>=20
>>>>> state one {
>>>>> if ( ! $net ) {
>>>>> run "/usr/local/testdown.sh"
>>>>> set-state two
>>>>> }
>>>>> }
>>>>>=20
>>>>> state two {
>>>>> if ( $net ) {
>>>>> run "/usr/local/testup.sh"
>>>>> set-state one
>>>>> }
>>>>> }
>>>>> =3D=3D=3D
>>>>>=20
>>>>> Is there any possibility to define and set ifstated.conf that
>>>> reacts when:
>>>>>=20
>>>>> any one of the carp interfaces is down - followed by
>>> another any
>>>>> other carp interface down
>>>>>=20
>>>>>=20
>>>>> I tried to define states:
>>>>>=20
>>>>> duu =3D"!carp0.link.up && carp1.link.up && carp2.link.up"
>>>>> udu =3D"carp0.link.up && !carp1.link.up && carp2.link.up"
>>>>> uud =3D"carp0.link.up && carp1.link.up && !carp2.link.up"
>>>>> ddu =3D"!carp0.link.up && !carp1.link.up"
>>>>> dud =3D"!carp0.link.up && !carp2.link.up"
>>>>> udd =3D"!carp1.link.up && !carp2.link.up"
>>>>>=20
>>>>> and used them but somehow I cannot incorporate all state
>>> changes and
>>>>> include it in ifstated.conf.
>>>>>=20
>>>>=20
>>>>=20
>>>> Works fine here, did you not have any luck with the file I
>>> posted
>>>> earlier ?
>>>> _______________________________________________
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>>> <mailto:freebsd-questions@freebsd.org>
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>>>>=20
>>>>=20
>>>=20
>>>=20
>>=20
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