Atlanta PTG Summary: Ironic (part 4)
This is an extract from my personal notes and public etherpads from the OpenStack PTG 2017 in Atlanta. A lot of text ahead!
Future Work (cont)
This was discussed on the last design summit. Since then we've got a nova spec, which, however, hasn't got many reviews so far. The spec continues using block_device_mapping_v2, other options apparently were not considered.
We discussed how to inform Nova whether or not RAID can be built for a particular node. Ideally, we need to tell the scheduler about many things: RAID support, disk number, disk sizes. We decided that it's an overkill, at least for the beginning. We'll only rely on a "supports RAID" trait for now.
It's still unclear what to do about local_gb property, but with planned Nova changes it may not be required any more.
There is a desire for flexible partitioning in ironic, both in case of partition and whole disk images (in the latter case - partition other disks). Generally, there was no consensus on the PTG. Some people were very much in favor of this feature, some - quite against. It's unclear how to pass partitioning information from Nova. There is a concern that such feature will get us too much into OS-specific details. We agreed that someone interested will collect the requirements, create a more detailed proposal, and we'll discuss it on the next PTG.
Splitting nodes into separate pools
This feature is about dedicating some nodes to a tenant, essentially adding a tenant_id field to nodes. This can be helpful e.g. for a hardware provider to reserve hardware for a tenant, so that it's always available.
This seems relatively easy to implement in Ironic. We need a new field on nodes, then only show non-admin users their hardware. A bit trickier to make it work with Nova. We agreed to investigate passing a token from Nova to Ironic, as opposed to always using a service user admin token.
- vdrok to work out the details and propose a spec.
Requirements for routed networks
We discussed requirements for achieving routed architecture like spine-and-leaf. It seems that most of the requirements are already in our plans. The outstanding items are:
- Multiple subnets support for ironic-inspector. Can be solved in dnsmasq.conf level, an appropriate change was merged into puppet-ironic.
- Per-node provision and cleaning networks. There is an RFE, somebody just has to do the work.
This does not seem to be a Pike goal for us, but many of the dependencies are planned for Pike.
Configuring BIOS setting for nodes
Preparing a node to be configured to serve a certain rule by tweaking its settings. Currently, it is implemented by the Drac driver in a vendor pass-thru.
We agreed that such feature would better fit cleaning, rather then pre-deployment. Thus, it does not depend on deploy steps. It was suggested to extend the management interface to support passing it an arbitrary JSON with configuration. Then a clean step would pick it (similar to RAID).
- rpioso to write a spec for this feature.
We discussed the deploy steps proposal in depth. We agreed on partially splitting the deployment procedure into pluggable bits. We will leave the very core of the deployment - flashing the image onto a target disk - hardcoded, at least for now. The drivers will be able to define steps to run before and after this core deployment. Pre- and post-deployment steps will have different priorities ranges, something like:
0 < pre-max/deploy-min < deploy-max/post-min < infinity
We plan on making partitioning a pre-deploy step, and installing a bootloader a post-deploy step. We will not allow IPA hardware managers to define deploy steps, at least for now.
- yolanda is planning to work on this feature, rloo and TheJulia to help.
IPA HTTP endpoints, and the endpoints Ironic provides for ramdisk callbacks are completely insecure right now. We hesitated to add any authentication to them, as any secrets published for the ramdisk to use (be it part of kernel command line or image itself) are readily available to anyone on the network.
We agreed on several things to look into:
- A random CSRF-like token to use for each node. This will somewhat limit the attack surface by requiring an attacker to intercept a token for the specific node, rather then just access the endpoints.
- Document splitting out public and private Ironic API as part of our future reference architecture guide.
- Make sure we support TLS between Ironic and IPA, which is particularly helpful when virtual media is used (and secrets are not leaked).
- jroll and joanna to look into the random token idea. jroll to write an RFE for TLS between IPA and Ironic.
- Using ansible-networking as a ML2 driver for ironic-neutron integration work
- It was suggested to make it one of backends for networking-generic-switch in addition to netmiko. Potential concurrency issues when using SSH were raised, and still require a solution.
- Extending and standardizing the list of capabilities the drivers may discover
- It was proposed to use os-traits for standardizing qualitative capabilities. jroll will look into quantitative capabilities.
- Pluggable interface for long-running processes
- This was proposed as an optional way to mitigate certain problems with local long-running services, like console. E.g. if a conductor crashes, its console services keep running. It was noted that this is a bug to be fixed (TheJulia volunteered to triage it). The proposed solution involved optionally run processes on a remote cluster, e.g. k8s. Concerns were voiced on the PTG around complicating support matrix and adding more decisions to make for operators. There was no apparent consensus on implementing this feature due to that.
- Setting specific boot device for PXE booting
- It was found to be already solved by setting pxe_enabled on ports. We just need to update ironic-inspector to set this flag.
Priorities and planning
The suggested priorities list is now finalized in https://review.openstack.org/439710.
We also agreed on the following priorities for ironic-inspector subteam:
- Inspector HA (milan)
- Community goal - python 3.5 (JayF, hurricanerix)
- Community goal - devstack+apache+wsgi (aarefiev, ovoshchana)
- Inspector needs to update pxe_enabled flag on ports (dtantsur)