Re: [Freeipa-devel] Adding a new DNA plugin configuration in IPAv3

2012-02-02 Thread Simo Sorce
On Thu, 2012-02-02 at 13:39 +0200, Alexander Bokovoy wrote:
> On Thu, 02 Feb 2012, Sumit Bose wrote:
> > Simo, thank you for give detailed responses and explanations here. To
> > make it - hopefully - even clearer I try to describe the step that are
> > necessary to enable IPA for trust and to create trust to AD domains.
> > 
> > I assume that we start from a running IPAv2 setup with replication:
> > 
> > 1. Update IPA to v3, install the new packages, run everything that is
> > needed for the update. This step will not create anything related to
> > trust (only the needed python code and config file templates are
> > installed)
> > 
> > 2. Call ipa-adtrust-install to enable IPA to handle trust, this will
> >   - create the samba configuration
> >   - add cn=trust to the DIT
> >   - generate a domain SID and stores it in the DIT
> >   - add the well know administrator and admin group SIDs to the admin user
> > and the admins group respectively
> >   - activate the CLDAP directory server plugin
> >   - add DNA configuration to automatically add SIDs to users and groups
> > on the server where ipa-adtrust-install
> At this point 'ipa trust ...' set of commands mentioned in (5) will be 
> able to operate because we'll have enough information about our own 
> domain to proceed with trusts to other domains.
> 
> 
> > 3. Now SIDs can be added to users and groups, this can be done
> >   - as Simo mentioned above with the help of a directory server task to
> > generate them as fast a possible
> >   - but if there are concerns about the traffic caused by the
> > replication, this can also be done by an external script, with a
> > rate limitation or during non-office hours
> > this process might take some time, but since it has to be done only once
> > I think it is even acceptable if it needs some days to finish, as long
> > as it is documented :-)
> Agree. 
> 
> There are two separate phases here, actually:
>   - trust creation
>   - trust usage
> 
> Normal usage is possible after step (3), creating trusts is possible 
> before (3), albeight it wouldn't be quite usable besides administrator 
> account.
>  
> > 4. Now ipa-adtrust-install can be called on other IPA servers which will
> > now skip the configuration steps which can already be found in the
> > replicated tree, some of the remaining ones are:
> >   - create the samba configuration
> >   - activate the CLDAP directory server plugin
> >   - add SID DNA configuration with an empty range
> ACK. There is also need to add DNS records to get these IPA servers in 
> use for AD discovery.

This is actually critical, the other servers need to have the DNA plugin
properly configured, otherwise creating a user on another server will
not add the SID, and we will have some users missing them.

So I am thinking that we have 2 strategies here:

- Require we run a ipa-trust-prepare script on all masters before we
populate users

- Add a new plugin, enabled by default at upgrade time, that is able to
detect trust were activated, and when that happens it automatically adds
the CLDAP and DNA plugins needed configuration. There is also the
problem of the samba configuration (Still the server will need a restart
so it is not a complete solution I guess).

The second would be nice, but it seem a lot more complex than what we
can afford for a first release and still has some gotchas.

Also we need to consider that we may not want to make all servers expose
samba and cldap. In most cases admins would want to enable only servers
that are close to the AD domain they want to trust.

So we need the DNA plugin configured everywhere, because it works at
user creation, but we need to be able to *not* configure samba, cldap
(and _msdcs DNS records) where not wanted.

We will also need a way to show which servers are 'trust' enabled so
that admins can easily inspect their setup.

> > 5. Finally a trust to an AD domain can be created my calling 'net rpc
> > trust create ...' (Alexander is working on the integration into the ipa
> > utility so that it will be more like 'ipa adtrust-create' or similar).
> Yep.

ack to all the rest.

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York

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Re: [Freeipa-devel] Adding a new DNA plugin configuration in IPAv3

2012-02-02 Thread Alexander Bokovoy
On Thu, 02 Feb 2012, Sumit Bose wrote:
> Simo, thank you for give detailed responses and explanations here. To
> make it - hopefully - even clearer I try to describe the step that are
> necessary to enable IPA for trust and to create trust to AD domains.
> 
> I assume that we start from a running IPAv2 setup with replication:
> 
> 1. Update IPA to v3, install the new packages, run everything that is
> needed for the update. This step will not create anything related to
> trust (only the needed python code and config file templates are
> installed)
> 
> 2. Call ipa-adtrust-install to enable IPA to handle trust, this will
>   - create the samba configuration
>   - add cn=trust to the DIT
>   - generate a domain SID and stores it in the DIT
>   - add the well know administrator and admin group SIDs to the admin user
> and the admins group respectively
>   - activate the CLDAP directory server plugin
>   - add DNA configuration to automatically add SIDs to users and groups
> on the server where ipa-adtrust-install
At this point 'ipa trust ...' set of commands mentioned in (5) will be 
able to operate because we'll have enough information about our own 
domain to proceed with trusts to other domains.


> 3. Now SIDs can be added to users and groups, this can be done
>   - as Simo mentioned above with the help of a directory server task to
> generate them as fast a possible
>   - but if there are concerns about the traffic caused by the
> replication, this can also be done by an external script, with a
> rate limitation or during non-office hours
> this process might take some time, but since it has to be done only once
> I think it is even acceptable if it needs some days to finish, as long
> as it is documented :-)
Agree. 

There are two separate phases here, actually:
- trust creation
- trust usage

Normal usage is possible after step (3), creating trusts is possible 
before (3), albeight it wouldn't be quite usable besides administrator 
account.
 
> 4. Now ipa-adtrust-install can be called on other IPA servers which will
> now skip the configuration steps which can already be found in the
> replicated tree, some of the remaining ones are:
>   - create the samba configuration
>   - activate the CLDAP directory server plugin
>   - add SID DNA configuration with an empty range
ACK. There is also need to add DNS records to get these IPA servers in 
use for AD discovery.

 
> 5. Finally a trust to an AD domain can be created my calling 'net rpc
> trust create ...' (Alexander is working on the integration into the ipa
> utility so that it will be more like 'ipa adtrust-create' or similar).
Yep.

-- 
/ Alexander Bokovoy

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Re: [Freeipa-devel] Adding a new DNA plugin configuration in IPAv3

2012-02-02 Thread Sumit Bose
On Wed, Feb 01, 2012 at 01:59:15PM -0500, Simo Sorce wrote:
> On Wed, 2012-02-01 at 12:00 -0500, Dmitri Pal wrote:
> > On 01/31/2012 06:45 AM, Sumit Bose wrote:
> > > Hi,
> > >
> > > for the IPAv3 trust feature we have to add the objectclass
> > > ipaNTUserAttrs/ipaNTGroupAttrs to every user/group which should be
> > > visible on the Windows side of the trust. The only MUST attribute of
> > > both objectclasses is ipaNTSecurityIdentifier the SID or the user or
> > > group. We would like to manage the SIDS with the DNA plugin since they
> > > have to be unique in the IPA domain.
> > >
> > > The trust support will typically be added to a running IPA domain,
> > > because we do not plan to install it by default and we have to consider
> > > updated v2 environments as well. So the question arises what is the most
> > > preferred way to add a DNA configuration to an existing Directory Server
> > > setup with replication.
> > >
> > > Nathan suggested to create the configuration with the full range on the
> > > first master, configure the other master with no available values
> > > and let the DNA plugin transfer the ranges between the masters.
> 
> This is the way to go.
> 
> > > This will lead to the following steps:
> > >
> > > 1. Check if there are already shared configuration entries in
> > >cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
> > >
> > > 2a. if not we can create the initial configuration on the current
> > > master:
> > >
> > > dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
> > > changetype: add
> > > objectclass: top
> > > objectclass: extensibleObject
> > > cn: SIDs
> > > dnaType: ipaNTSecurityIdentifier
> > > dnaNextValue: 1000
> > > dnaMaxValue: eval($SIDMAX)# Maybe 200k ?
> > > dnaMagicRegen: 999
> > > dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
> > > dnaScope: $SUFFIX
> > > dnaThreshold: 500
> > > dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
> > >
> > > 3a. Add ipaNTUserAttrs/ipaNTGroupAttrs to all users/groups with
> > > ipaNTSecurityIdentifier=999 on the current master
> 
> This should be done as a task in Directory server.
> 
> > > 4a. Done on the first master
> 
> I am not sure I understand what does this means.
> 
> > > 2b. if there are already entries we can create the configuration for an
> > > additional master:
> > >
> > > dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
> > > changetype: add
> > > objectclass: top
> > > objectclass: extensibleObject
> > > cn: SIDs
> > > dnaType: ipaNTSecurityIdentifier
> > > dnaNextValue: 1101
> > > dnaMaxValue: 1100
> > > dnaMagicRegen: 999
> > > dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
> > > dnaScope: $SUFFIX
> > > dnaThreshold: 500
> > > dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
> > >
> > > 3b. Done on the additional master, DNA plugin will sort out the rest
> > >
> > >
> > >
> > > Do these steps make sense?
> 
> Yes.
> 
> > > Is it necessary to add a lock to prevent a race condition btween step 1
> > > and 2a, i.e. two admins try to prepare IPA for trusts independently at
> > > the same time?
> 
> No, if admins are so dumb not to coordinate on adding this
> infrastructure changing stuff and do it at the exact same moment it's
> really their problem. We will, of course, document that they should be
> careful.
> 
> > > Do I understand it correctly that if dnaMaxValue is set to e.g. 2^32 on
> > > the first master, the range on the second master will start at 2^31? So
> > > the usage of the full range will be quite sparse if dnaMaxValue is set
> > > too high.
> 
> True, ranges are always split in half for now.
> 
> > > Step 3a on the first master might need some time to finish. Is it
> > > necessary to set some kind of lock to prevent the configuration of the
> > > DNA plugin on other masters while this task is running or is it safe to
> > > add another master at any time?
> 
> safe, the task to add SIDs to users should be an explicit DS task set up
> only by the ipa-trust-install script.
> 
> > > Are there other ways to introduce the DNA configuration? Nathan
> > > suggested also that the ranges can be configured manually without
> > > overlap, but if possible I would prefer the automatic way.
> 
> Automatic is better, less error prone.
> 
> > Couple comments.
> > 1) What is the impact on the replication?
> 
> If you have many users the first replication would take a long time.
> 
> > 2) How we can prevent the case when in the distributed topology the
> > change starts from two ends?
> 
> By documenting that you do not run ipa-trust-install on 2 ends.
> 
> > 3) What is the speed of the propagation of this configuration in a 20
> > replica architecture?
> 
> It depends on the replica topology and what master you run the install
> on.
> 
> > 4) Would it be better to generate the SIDs on every replica? We already
> > have UID/GID and GUIDs for the entries. If SID is derived from entry
> > GUID the change can be 

Re: [Freeipa-devel] Adding a new DNA plugin configuration in IPAv3

2012-02-01 Thread Simo Sorce
On Wed, 2012-02-01 at 13:39 -0500, Rob Crittenden wrote:
> Sumit Bose wrote:
> > Hi,
> >
> > for the IPAv3 trust feature we have to add the objectclass
> > ipaNTUserAttrs/ipaNTGroupAttrs to every user/group which should be
> > visible on the Windows side of the trust. The only MUST attribute of
> > both objectclasses is ipaNTSecurityIdentifier the SID or the user or
> > group. We would like to manage the SIDS with the DNA plugin since they
> > have to be unique in the IPA domain.
> >
> > The trust support will typically be added to a running IPA domain,
> > because we do not plan to install it by default and we have to consider
> > updated v2 environments as well. So the question arises what is the most
> > preferred way to add a DNA configuration to an existing Directory Server
> > setup with replication.
> >
> > Nathan suggested to create the configuration with the full range on the
> > first master, configure the other master with no available values
> > and let the DNA plugin transfer the ranges between the masters.
> >
> > This will lead to the following steps:
> >
> > 1. Check if there are already shared configuration entries in
> > cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
> >
> > 2a. if not we can create the initial configuration on the current
> >  master:
> >
> > dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
> > changetype: add
> > objectclass: top
> > objectclass: extensibleObject
> > cn: SIDs
> > dnaType: ipaNTSecurityIdentifier
> > dnaNextValue: 1000
> > dnaMaxValue: eval($SIDMAX)# Maybe 200k ?
> > dnaMagicRegen: 999
> > dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
> > dnaScope: $SUFFIX
> > dnaThreshold: 500
> > dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
> >
> > 3a. Add ipaNTUserAttrs/ipaNTGroupAttrs to all users/groups with
> >  ipaNTSecurityIdentifier=999 on the current master
> >
> > 4a. Done on the first master
> >
> > 2b. if there are already entries we can create the configuration for an
> >  additional master:
> >
> > dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
> > changetype: add
> > objectclass: top
> > objectclass: extensibleObject
> > cn: SIDs
> > dnaType: ipaNTSecurityIdentifier
> > dnaNextValue: 1101
> > dnaMaxValue: 1100
> > dnaMagicRegen: 999
> > dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
> > dnaScope: $SUFFIX
> > dnaThreshold: 500
> > dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
> >
> > 3b. Done on the additional master, DNA plugin will sort out the rest
> >
> >
> >
> > Do these steps make sense?
> >
> > Is it necessary to add a lock to prevent a race condition btween step 1
> > and 2a, i.e. two admins try to prepare IPA for trusts independently at
> > the same time?
> 
> There is no locking/notification mechansim to do this AFAIK.
> 
> The "first master" in this case really means the first one that gets 
> updated packages. The updates that happen at rpm upgrade time happen 
> with the server listening only on ldapi so it would be very possible for 
> two servers to apply the updates at the same time without knowing it.

The trust stuff is always explicitly installed manually, so there is no
problem at rpm upgrade time. Either the configuration is already there
or there is no configuration to care about.

> > Do I understand it correctly that if dnaMaxValue is set to e.g. 2^32 on
> > the first master, the range on the second master will start at 2^31? So
> > the usage of the full range will be quite sparse if dnaMaxValue is set
> > too high.
> >
> > Step 3a on the first master might need some time to finish. Is it
> > necessary to set some kind of lock to prevent the configuration of the
> > DNA plugin on other masters while this task is running or is it safe to
> > add another master at any time?
> 
> In fact it might take a REALLY long time if there are a lot of users. 
> This would happen at the end of an rpm upgrade, I wonder if we'd want a 
> separate task to run instead.

Nothing to do at rpm updagrade time.

> If we can figure out a way to have only one server do all the updates 
> then I don't think the DNA config would be an issue.

Only one server should do them see my other email.

> > Are there other ways to introduce the DNA configuration? Nathan
> > suggested also that the ranges can be configured manually without
> > overlap, but if possible I would prefer the automatic way.
> 
> I think coordinating manual ranges would be hard, I agree with Sumit 
> that automatic is the way to go.
> 
> I wonder if before shutting things down for upgrade something creates 
> cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX and sets a magic value in it 
> specific to the host that added it.
> 
> When any other changes are done relating to this update if the hostname 
> doesn't match that magic value the updates are skipped.
> 
> We tend to construct full dns for reference rather than searching so I'd 
> think that even if there was a replication 

Re: [Freeipa-devel] Adding a new DNA plugin configuration in IPAv3

2012-02-01 Thread Simo Sorce
On Wed, 2012-02-01 at 12:00 -0500, Dmitri Pal wrote:
> On 01/31/2012 06:45 AM, Sumit Bose wrote:
> > Hi,
> >
> > for the IPAv3 trust feature we have to add the objectclass
> > ipaNTUserAttrs/ipaNTGroupAttrs to every user/group which should be
> > visible on the Windows side of the trust. The only MUST attribute of
> > both objectclasses is ipaNTSecurityIdentifier the SID or the user or
> > group. We would like to manage the SIDS with the DNA plugin since they
> > have to be unique in the IPA domain.
> >
> > The trust support will typically be added to a running IPA domain,
> > because we do not plan to install it by default and we have to consider
> > updated v2 environments as well. So the question arises what is the most
> > preferred way to add a DNA configuration to an existing Directory Server
> > setup with replication.
> >
> > Nathan suggested to create the configuration with the full range on the
> > first master, configure the other master with no available values
> > and let the DNA plugin transfer the ranges between the masters.

This is the way to go.

> > This will lead to the following steps:
> >
> > 1. Check if there are already shared configuration entries in
> >cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
> >
> > 2a. if not we can create the initial configuration on the current
> > master:
> >
> > dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
> > changetype: add
> > objectclass: top
> > objectclass: extensibleObject
> > cn: SIDs
> > dnaType: ipaNTSecurityIdentifier
> > dnaNextValue: 1000
> > dnaMaxValue: eval($SIDMAX)# Maybe 200k ?
> > dnaMagicRegen: 999
> > dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
> > dnaScope: $SUFFIX
> > dnaThreshold: 500
> > dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
> >
> > 3a. Add ipaNTUserAttrs/ipaNTGroupAttrs to all users/groups with
> > ipaNTSecurityIdentifier=999 on the current master

This should be done as a task in Directory server.

> > 4a. Done on the first master

I am not sure I understand what does this means.

> > 2b. if there are already entries we can create the configuration for an
> > additional master:
> >
> > dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
> > changetype: add
> > objectclass: top
> > objectclass: extensibleObject
> > cn: SIDs
> > dnaType: ipaNTSecurityIdentifier
> > dnaNextValue: 1101
> > dnaMaxValue: 1100
> > dnaMagicRegen: 999
> > dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
> > dnaScope: $SUFFIX
> > dnaThreshold: 500
> > dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
> >
> > 3b. Done on the additional master, DNA plugin will sort out the rest
> >
> >
> >
> > Do these steps make sense?

Yes.

> > Is it necessary to add a lock to prevent a race condition btween step 1
> > and 2a, i.e. two admins try to prepare IPA for trusts independently at
> > the same time?

No, if admins are so dumb not to coordinate on adding this
infrastructure changing stuff and do it at the exact same moment it's
really their problem. We will, of course, document that they should be
careful.

> > Do I understand it correctly that if dnaMaxValue is set to e.g. 2^32 on
> > the first master, the range on the second master will start at 2^31? So
> > the usage of the full range will be quite sparse if dnaMaxValue is set
> > too high.

True, ranges are always split in half for now.

> > Step 3a on the first master might need some time to finish. Is it
> > necessary to set some kind of lock to prevent the configuration of the
> > DNA plugin on other masters while this task is running or is it safe to
> > add another master at any time?

safe, the task to add SIDs to users should be an explicit DS task set up
only by the ipa-trust-install script.

> > Are there other ways to introduce the DNA configuration? Nathan
> > suggested also that the ranges can be configured manually without
> > overlap, but if possible I would prefer the automatic way.

Automatic is better, less error prone.

> Couple comments.
> 1) What is the impact on the replication?

If you have many users the first replication would take a long time.

> 2) How we can prevent the case when in the distributed topology the
> change starts from two ends?

By documenting that you do not run ipa-trust-install on 2 ends.

> 3) What is the speed of the propagation of this configuration in a 20
> replica architecture?

It depends on the replica topology and what master you run the install
on.

> 4) Would it be better to generate the SIDs on every replica? We already
> have UID/GID and GUIDs for the entries. If SID is derived from entry
> GUID the change can be made locally and does not require replication.

SIDs cannot be derived from GUIDs.

> The GUIDs are already replicated so the SID can be generated locally
> like we do with the other non replicated attributes. In this case you
> just need to install a new plugin on your replicas and change
> configuration entry to 

Re: [Freeipa-devel] Adding a new DNA plugin configuration in IPAv3

2012-02-01 Thread Rob Crittenden

Sumit Bose wrote:

Hi,

for the IPAv3 trust feature we have to add the objectclass
ipaNTUserAttrs/ipaNTGroupAttrs to every user/group which should be
visible on the Windows side of the trust. The only MUST attribute of
both objectclasses is ipaNTSecurityIdentifier the SID or the user or
group. We would like to manage the SIDS with the DNA plugin since they
have to be unique in the IPA domain.

The trust support will typically be added to a running IPA domain,
because we do not plan to install it by default and we have to consider
updated v2 environments as well. So the question arises what is the most
preferred way to add a DNA configuration to an existing Directory Server
setup with replication.

Nathan suggested to create the configuration with the full range on the
first master, configure the other master with no available values
and let the DNA plugin transfer the ranges between the masters.

This will lead to the following steps:

1. Check if there are already shared configuration entries in
cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX

2a. if not we can create the initial configuration on the current
 master:

dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
changetype: add
objectclass: top
objectclass: extensibleObject
cn: SIDs
dnaType: ipaNTSecurityIdentifier
dnaNextValue: 1000
dnaMaxValue: eval($SIDMAX)# Maybe 200k ?
dnaMagicRegen: 999
dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
dnaScope: $SUFFIX
dnaThreshold: 500
dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX

3a. Add ipaNTUserAttrs/ipaNTGroupAttrs to all users/groups with
 ipaNTSecurityIdentifier=999 on the current master

4a. Done on the first master

2b. if there are already entries we can create the configuration for an
 additional master:

dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
changetype: add
objectclass: top
objectclass: extensibleObject
cn: SIDs
dnaType: ipaNTSecurityIdentifier
dnaNextValue: 1101
dnaMaxValue: 1100
dnaMagicRegen: 999
dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
dnaScope: $SUFFIX
dnaThreshold: 500
dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX

3b. Done on the additional master, DNA plugin will sort out the rest



Do these steps make sense?

Is it necessary to add a lock to prevent a race condition btween step 1
and 2a, i.e. two admins try to prepare IPA for trusts independently at
the same time?


There is no locking/notification mechansim to do this AFAIK.

The "first master" in this case really means the first one that gets 
updated packages. The updates that happen at rpm upgrade time happen 
with the server listening only on ldapi so it would be very possible for 
two servers to apply the updates at the same time without knowing it.




Do I understand it correctly that if dnaMaxValue is set to e.g. 2^32 on
the first master, the range on the second master will start at 2^31? So
the usage of the full range will be quite sparse if dnaMaxValue is set
too high.

Step 3a on the first master might need some time to finish. Is it
necessary to set some kind of lock to prevent the configuration of the
DNA plugin on other masters while this task is running or is it safe to
add another master at any time?


In fact it might take a REALLY long time if there are a lot of users. 
This would happen at the end of an rpm upgrade, I wonder if we'd want a 
separate task to run instead.


If we can figure out a way to have only one server do all the updates 
then I don't think the DNA config would be an issue.



Are there other ways to introduce the DNA configuration? Nathan
suggested also that the ranges can be configured manually without
overlap, but if possible I would prefer the automatic way.


I think coordinating manual ranges would be hard, I agree with Sumit 
that automatic is the way to go.


I wonder if before shutting things down for upgrade something creates 
cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX and sets a magic value in it 
specific to the host that added it.


When any other changes are done relating to this update if the hostname 
doesn't match that magic value the updates are skipped.


We tend to construct full dns for reference rather than searching so I'd 
think that even if there was a replication conflict entry created it 
would never get used because of the unique dn it would get.


rob

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Re: [Freeipa-devel] Adding a new DNA plugin configuration in IPAv3

2012-02-01 Thread Dmitri Pal
On 01/31/2012 06:45 AM, Sumit Bose wrote:
> Hi,
>
> for the IPAv3 trust feature we have to add the objectclass
> ipaNTUserAttrs/ipaNTGroupAttrs to every user/group which should be
> visible on the Windows side of the trust. The only MUST attribute of
> both objectclasses is ipaNTSecurityIdentifier the SID or the user or
> group. We would like to manage the SIDS with the DNA plugin since they
> have to be unique in the IPA domain.
>
> The trust support will typically be added to a running IPA domain,
> because we do not plan to install it by default and we have to consider
> updated v2 environments as well. So the question arises what is the most
> preferred way to add a DNA configuration to an existing Directory Server
> setup with replication.
>
> Nathan suggested to create the configuration with the full range on the
> first master, configure the other master with no available values
> and let the DNA plugin transfer the ranges between the masters.
>
> This will lead to the following steps:
>
> 1. Check if there are already shared configuration entries in
>cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
>
> 2a. if not we can create the initial configuration on the current
> master:
>
> dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
> changetype: add
> objectclass: top
> objectclass: extensibleObject
> cn: SIDs
> dnaType: ipaNTSecurityIdentifier
> dnaNextValue: 1000
> dnaMaxValue: eval($SIDMAX)# Maybe 200k ?
> dnaMagicRegen: 999
> dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
> dnaScope: $SUFFIX
> dnaThreshold: 500
> dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
>
> 3a. Add ipaNTUserAttrs/ipaNTGroupAttrs to all users/groups with
> ipaNTSecurityIdentifier=999 on the current master
>
> 4a. Done on the first master
>
> 2b. if there are already entries we can create the configuration for an
> additional master:
>
> dn: cn=SIDs,cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config
> changetype: add
> objectclass: top
> objectclass: extensibleObject
> cn: SIDs
> dnaType: ipaNTSecurityIdentifier
> dnaNextValue: 1101
> dnaMaxValue: 1100
> dnaMagicRegen: 999
> dnaFilter: (|(objectclass=ipaNTUserAttrs)(objectClass=ipaNTGroupAttrs))
> dnaScope: $SUFFIX
> dnaThreshold: 500
> dnaSharedCfgDN: cn=sids,cn=dna,cn=ipa,cn=etc,$SUFFIX
>
> 3b. Done on the additional master, DNA plugin will sort out the rest
>
>
>
> Do these steps make sense?
>
> Is it necessary to add a lock to prevent a race condition btween step 1
> and 2a, i.e. two admins try to prepare IPA for trusts independently at
> the same time?
>
> Do I understand it correctly that if dnaMaxValue is set to e.g. 2^32 on
> the first master, the range on the second master will start at 2^31? So
> the usage of the full range will be quite sparse if dnaMaxValue is set
> too high.
>
> Step 3a on the first master might need some time to finish. Is it
> necessary to set some kind of lock to prevent the configuration of the
> DNA plugin on other masters while this task is running or is it safe to
> add another master at any time?
>
> Are there other ways to introduce the DNA configuration? Nathan
> suggested also that the ranges can be configured manually without
> overlap, but if possible I would prefer the automatic way.
>
> Thank you for your help.
>
> bye,
> Sumit
>
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>

Couple comments.
1) What is the impact on the replication?
2) How we can prevent the case when in the distributed topology the
change starts from two ends?
3) What is the speed of the propagation of this configuration in a 20
replica architecture?
4) Would it be better to generate the SIDs on every replica? We already
have UID/GID and GUIDs for the entries. If SID is derived from entry
GUID the change can be made locally and does not require replication.
The GUIDs are already replicated so the SID can be generated locally
like we do with the other non replicated attributes. In this case you
just need to install a new plugin on your replicas and change
configuration entry to enable it. As soon as this entry is replicated
the plugin will kick in and would start adding SIDs to users and groups
in the background on every replica. Overall there will be less traffic
and no need to deal with DNA ranges. Is it possible to derive SID from
other attribute in the User or group object?
5) If we go with the way Summit suggested we also need to have a special
handling in the ipa-replica-prepare depending upon whether the SID
support is on or off.   

-- 
Thank you,
Dmitri Pal

Sr. Engineering Manager IPA project,
Red Hat Inc.


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