Commit 804ee5ff authored by Helga Velroyen's avatar Helga Velroyen

Updates of design doc

With the progressing implementation of the design
'design-node-security.rst', some aspects of the design
were changed or detailed. This patch brings the
design back in sync with the implementation.

Changes cover:
- Cleanup of public keys and authorized keys of
  nodes before they are readded.
- Fixing version number to 2.13, where the main
  changes in the SSH implementation are made.
- Mention new --new-ssh-key option of
  'gnt-cluster renew-crypto'.
- Mention compliance with options to suppress
  SSH file manipulation.
Signed-off-by: default avatarHelga Velroyen <>
Reviewed-by: default avatarKlaus Aehlig <>
parent 1be25340
......@@ -234,7 +234,13 @@ In case of readding a node that used to be in the cluster before,
handling of the SSH keys would basically be the same, in particular also
a new SSH key pair is generated for the node, because we cannot be sure
that the old key pair has not been compromised while the node was
offlined. Note that for reasons of data hygiene, a node's
``ganeti_pub_keys`` file is cleared before the node is readded.
Also, Ganeti attempts to remove any Ganeti keys from the ``authorized_keys``
file before the node is readded. However, since Ganeti does not keep a list
of all keys ever used in the cluster, this applies only to keys which
are currently used in the cluster. Note that Ganeti won't touch any keys
that were added to the ``authorized_keys`` by other systems than Ganeti.
Pro- and demoting a node to/from master candidate
......@@ -299,7 +305,7 @@ The same behavior should be ensured for the corresponding rapi command.
Cluster verify
So far, 'gnt-cluster verify' checks the SSH connectivity of all nodes to
So far, ``gnt-cluster verify`` checks the SSH connectivity of all nodes to
all other nodes. We propose to replace this by the following checks:
- For all master candidates, we check if they can connect any other node
......@@ -340,7 +346,7 @@ will be backed up and not simply overridden.
These downgrading steps will be implemtented from 2.12 to 2.11:
These downgrading steps will be implemtented from 2.13 to 2.12:
- The master node's private/public key pair will be distributed to all
nodes (via SSH) and the individual SSH keys will be backed up.
......@@ -351,8 +357,26 @@ These downgrading steps will be implemtented from 2.12 to 2.11:
The ``gnt-cluster renew-crypto`` command is not affected by the proposed
changes related to SSH.
The ``gnt-cluster renew-crypto`` command will be extended by a new
option ``--new-ssh-keys``, which will renew all SSH keys on all nodes
and rebuild the ``authorized_keys`` files and the ``ganeti_pub_keys``
files according to the previous sections. This operation will be
performed considering the already stated security considerations, for
example minimizing RPC calls, distribution of keys via SSH only etc.
Compliance to --no-ssh-init and --no-node-setup
With this design, Ganeti will do more manipulations of SSH keys and
``authorized_keys`` files than before. If this is not feasible in
a Ganeti environment, the administrator has the option to prevent
Ganeti from performing any manipulations on the SSH setup of the nodes.
The options for doing so, are ``--no-ssh-init`` for ``gnt-cluster
init``, and ``--no-node-setup`` for ``gnt-node add``. Note that
these options already existed before the implementation of this
design, we just confirm that they will be complied to with the
new design as well.
Proposal regarding node daemon certificates
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