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5 October 2016

Testing out the TLS everywhere patches for TripleO

by Juan Antonio Osorio Robles

With the TLS-everywhere (powered by certmonger) patches accumulating in gerrit. It’s probably a good idea to write how I set up my development environment so others can do the same and try it out.

Physical setup

For all my development, I use only one node, where I run the virtual machines that comprise the TripleO deployment.

Since the setup needs a CA that’s trusted on all the nodes, I install FreeIPA on that same host, which will serve as our CA.

I don’t install it in one of the virtual machines for simplicity, since in this setup, the undercloud node and the overcloud nodes point to the hypervisor (that runs FreeIPA) as a DNS server, so we get that for free.

FreeIPA

To install FreeIPA with a very minimal configuraton (only for testing purposes), you can do the following command:

export DOMAIN=walrusdomain
export SECRET=SomePassword
ipa-server-install --realm=$(echo $DOMAIN | awk '{print toupper($0)}') \
    --admin-password=$SECRET --ds-password=$SECRET \
    --hostname=$(hostname -f) -U

Once this finishes you need to authenticate using the password you have (hopefully you’re using a different password than the one I put there). So we do:

# Get a kerberos ticket for the admin user
kinit admin
# verify we have a ticket
klist

Now, with FreeIPA installed and the kerberos ticket loaded, you need to set up the necessary hosts and services in FreeIPA for the overcloud deployment. You’ll also need to set up a hostname for the undercloud, since we need to enroll this too so it’s both tracked and it trusts FeeIPA as a CA.

For this, lets define two environment variables that we’ll use for this:

export SECRET=$(uuidgen)
export DOMAIN=walrusdomain

Where SECRET will be the OTP that we’ll use for the nodes to authenticate in the enrollment phase, and DOMAIN is the domain that we already set for FreeIPA (or the kerberos realm).

Note that the SECRET should preferably not be a human readable password, so in this case I’m using a UUID. This should be disposable anyway and is only used for enrollment. Also note that you’ll need to remember the UUID, since you’ll need to use the same one when you create the environment files to enroll the overcloud nodes.

To add the undercloud node we can do the following:

ipa host-add undercloud.$DOMAIN --password=$SECRET --force

Now, for the overcloud nodes, the number of hosts and services can vary depending on the deployment size. So to simplify this, I have a script that will do this for you. So, assuming that you’ll do an HA setup, lets do this:

git clone https://github.com/JAORMX/freeipa-tripleo-incubator.git
cd freeipa-tripleo-incubator
python create_ipa_tripleo_host_setup.py -w $SECRET -d $DOMAIN \
    --controller-count 3 --compute-count 1

This will create a node for each of the VIPs, 3 controller hosts and a relevant host for each node in each network (external, internalapi, storage, storagemgmt and ctlplane), and finally one compute host. On the other hand, it will create a haproxy service for the VIP hosts, and an HTTPD service for the controllers. Also, the controllers will manage the haproxy services. All of this is needed to request the appropriate certificates for the services from the overcloud nodes.

Hopefully everything went well, so now we can set up TripleO!

TripleO

Undercloud setup

Now, we need to position ourselves in the undercloud host. For this, I assume you already have a running undercloud host, and the overcloud nodes are ready to deploy. Now, one thing is that the FreeIPA host needs to be accessible from both the undercloud and the overcloud nodes, so make sure this is the case by attempting to ping that host using its FQDN.

For simplicity, lets say that the FreeIPA node’s FQDN is “ipa” + the kerberos realm:

export DOMAIN=walrusdomain
export IPA_SERVER="ipa.$DOMAIN"

On the other hand, we need to make sure that the undercloud node has the FQDN we specified to FreeIPA (including the domain.

sudo hostnamectl set-hostname undercloud.$DOMAIN

You can alternatively edit your /etc/hosts file

Now, we need to get the undercloud to trust FreeIPA as a CA. To do this, we’ll enroll the undercloud node with the following steps:

export SECRET='Something something'   #here goes the UUID from before

sudo yum install -y ipa-client
sudo ipa-client-install --server $IPA_SERVER \
    --password=$SECRET --domain=$DOMAIN --unattended

And we’re set! Now we can authenticate by using the keytab to get a kerberos ticket:

# Get kerberos ticket
sudo kinit -k -t /etc/krb5.keytab
# Verify we got a ticket
sudo klist

Now that we have the undercloud enrolled, lets prepare everything for the overcloud deploy.

Overcloud setup

Preparing the images

Now, before doing the deployment, we’ll need a couple of packages in the overcloud images so everything goes smoothly. We’ll need the ipa-client package (just like in the undercloud) and we’ll need mod_ssl (in case you’re also securing apache). So lets install those into the images:

# Install packages in the imge
virt-customize -a overcloud-full.qcow2 --install ipa-client,mod_ssl
# Upload images to undercloud's glance
openstack overcloud image upload --update-existing

Note that to get the virt-customize utility, you need to install libguestfs-tools (in CentOS).

Heat environment files

Our overcloud will need several things for the FreeIPA enrollment:

tripleo-common includes a script for this:

# Run script to generate environment file
create_freeipa_enroll_envfile.py -w $SECRET -d $DOMAIN -s $IPA_SERVER

This will output an environment file:

Now, as for the environment files needed that should be available in tripleo-heat-templates. These are the relevant environment files:

This tells certmonger to request the certificate for the public endpoint of HAProxy:

tripleo-heat-templates/environments/services/haproxy-public-tls-certmonger.yaml

Now, you could use a certificate and key and inject those as it’s always been done for the overcloud. However, for whoever needs it, there is FreeIPA support there as well

And to enable TLS in the internal network too, we can include this:

tripleo-heat-templates/environments/enable-internal-tls.yaml

This tells TripleO that the internal endpoints for HAProxy need to use TLS as well (and will attempt to get certificates for thsoe as well using certmonger), but also that the traffic in the internal networks needs to use TLS too. So, OpenStack services running over httpd get this in a fairly simple manner. However, services that don’t run httpd (mainly glance and swift) will have mod_proxy in front of them to terminate TLS.

Finally, This tells TripleO to set the endpoints to use TLS everywhere (it will be reflected in the keystone catalog):

tripleo-heat-templates/environments/tls-everywhere-endpoints-dns.yaml

tags: tripleo - openstack

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