Encrypting Ceph traffic in transit with msgr2 secure mode

Support depends on the kernel build you run, so confirm it with your distribution's release notes and the Ceph msgr2 documentation before you enable secure mode for those mounts. Kernel clients speak msgr2 only when the kernel includes that protocol support, and the mode they negotiate is controlled by the cluster's messenger settings. Check the kernel version on every host that maps RBD images or mounts CephFS, including hypervisors and backup nodes that people often forget. Test one mount end to end on a non-production pool, then confirm the connection mode on the live session before you change defaults for the whole fleet.

User-space clients built on librados and librbd can use msgr2 secure mode, but the exact set depends on the Ceph release each application links against. Confirm the library version that each application, hypervisor plugin or backup tool loads, not only the Ceph packages installed on the host. Bundled or statically linked libraries are a common gap, because an application can keep an older library after the operating system package is upgraded. Ask each application owner which library they use, run a connection test with secure mode enforced, and record the result alongside the client version so the evidence survives later upgrades.

Ceph daemons talk to each other over the messenger, so msgr2 secure mode can apply to monitor, OSD, manager and metadata traffic, and the cluster network settings decide which connections are affected. The Object Gateway (RGW) is different at the client-facing edge: S3 and Swift requests arrive over HTTP or HTTPS on the gateway, so you must configure TLS on that endpoint separately. Inside the cluster, RGW still connects to RADOS through the messenger, so check that its client mode matches your policy. Confirm each daemon type, its configuration section and the protocol each listener uses, because a secure internal path does not protect a plaintext client endpoint.

Mixed client versions are the main reason rollouts stall, because a client that cannot negotiate secure mode will either fail to connect or fall back, depending on the mode you set. Start by inventorying every client family and version, including kernel mounts, hypervisors, container images and backup agents. Then set the permissive setting first, observe which sessions are still unencrypted, and upgrade or reconfigure those clients before you require secure mode. Keep a dated list of clients that remain on older versions, because that list defines the window where traffic is not encrypted and it is the first thing an auditor will ask about.

The result depends on the mode you configure, and the safest test is to find out on a non-production cluster before you enforce anything. In a permissive configuration, a client that cannot use secure mode may still connect without encryption, which keeps services running but leaves that traffic exposed. In a strict configuration, the same client is refused, which protects the data path but can cause an outage if an unnoticed client depends on the cluster. Document the exact setting for each daemon type and client class, schedule a rollback step, and confirm that monitoring alerts on refused connections so the failure is visible to the operations team.

Confirm encryption on live sessions, not only in configuration files, because a setting can exist while some clients still connect in another mode. Use the monitoring and session commands documented for your Ceph release to list active connections and the protocol and mode each one negotiated. Sample connections from every client class, including kernel mounts, RGW and backup tools, and keep the output as evidence with the date and cluster version. Repeat the check after upgrades and after onboarding new applications, since a single new client with an old library can reintroduce unencrypted traffic.

Ask for a written inventory of every client family, its version and its owner, plus a test plan that shows the connection mode each class negotiates under permissive and strict settings. The review should cover kernel RBD and CephFS hosts, librados and librbd applications, RGW and other daemons, and a rollback procedure. Ask who is responsible for changing each client, because application teams often own the library upgrades. DeployOpen plans, implements and documents this kind of work in infrastructure you control and works from a fixed scope agreed in writing, so the quote follows from the inventory and the number of client classes involved.

Secure mode adds encryption work to each connection, so the effect depends on your hardware, workload pattern and the client's CPU budget, and no general figure applies to every cluster. The Ceph messenger v2 documentation describes AES-GCM encryption with integrity checks, but it does not give a universal overhead number, so measure it. Benchmark a representative client on the same hardware with secure mode off and on, using your own block sizes and concurrency, and compare latency and CPU use. Ask any partner to show these results for your environment before the change goes to production.

The cost is mostly labor: inventory, benchmarking, change planning, client testing and the maintenance windows that rollout requires. Secure mode adds CPU work for encrypting traffic, so the main technical driver is how much CPU headroom your OSD, monitor and gateway hosts already have at peak. Clusters with spare capacity usually see a smaller effort than clusters already running hot. Client upgrades are often the largest variable, because every application, hypervisor and gateway that connects must support the mode you choose. Ask any partner to split the quote into discovery, benchmarking, client testing, the change itself and post-change verification, and to state which items are one-time and which recur, such as re-verification after upgrades.

The rollout length depends mainly on cluster size, the number of distinct client types and how many change windows your operations calendar allows. A small cluster with a few well-understood clients is faster to change than a multi-site estate with many hypervisors, gateways and custom applications, because each client path needs its own test and sign-off. Larger clusters also take longer to roll through in stages so that you can watch health and latency between steps. No fixed duration applies to every environment, so ask for a schedule built from your own inventory and change calendar rather than a generic estimate.

Yes, if your team already operates the cluster, has a non-production environment that matches production closely enough to benchmark, and owns every client that connects to it. The configuration change itself is small, but the work around it is not: you need an accurate list of clients and their versions, a measured baseline for CPU and latency, a tested rollback path and staff available during the windows. Teams that lack one of these pieces, or that run storage for several internal owners, often find a fixed-scope engagement cheaper than pulling their own engineers off other work for the duration. DeployOpen plans, implements and documents this work inside your infrastructure, and the written scope sets what is included.

Three inputs matter most. First, an inventory of every component that talks to the cluster, including monitors, OSDs, managers, Object Gateway instances, RBD clients, CephFS mounts and any applications using librados directly, with the Ceph version and client library version of each. Second, a benchmark environment that resembles production in hardware, network and data layout, so CPU and latency results are meaningful. Third, agreed maintenance windows and named owners who can approve changes and make decisions during each window. Your team should also confirm which Ceph release line you run, because the supported behavior of each release is part of the planning.

Secure mode encrypts all post-authentication traffic with AES-GCM and adds integrity checks, so it uses more CPU than the default crc mode. How much more depends on hardware, the CPU instruction support on each host, network throughput and the I/O pattern of your workloads. Do not rely on a general percentage. Benchmark representative client traffic on hardware that matches production, measure OSD and gateway CPU at peak, and compare latency and throughput before and after. Pay attention to hosts that already run near their limits during recovery or scrubbing, because those periods are when extra CPU load is most likely to hurt client I/O.

Do not assume the setting took effect. Confirm the configured connection modes in the cluster configuration, check that each daemon and client negotiates secure mode after reconnecting, and test from the network side by capturing traffic between a client and an OSD or monitor on port 3300 and confirming the payload is not readable. Repeat the check for every client type, including older clients that may fall back to a weaker mode or fail to connect. Record the results as evidence, because auditors and security reviewers will ask how you verified the setting, not only what you configured. Ask any partner to include this verification step in the written deliverables.

Secure mode supports controls about protecting data in transit inside the storage cluster, but it does not make a system compliant on its own. It is one input to a wider set of requirements covering cryptography, access and logging. DeployOpen prepares systems, controls and evidence for compliance assessments, but it does not issue audit reports, attestations or certifications. Independent auditors and certification bodies make those determinations. Ask your assessor which evidence they expect for in-transit protection, such as configuration records, verification output and change approvals, and confirm that the scope of encryption matches the systems you need to cover.