# What privileged buys Why the agent’s container runs with privileged=yes by default, the sources that setting makes readable, and the network, processes and sensors it still does not reach. Source: https://jmrplens.github.io/mikroscope/limits/privileged/ `install` creates the agent's container with `privileged=yes`. This page answers what that setting changes on the router, which of the agent's sources depend on it, what it does not open however it is configured, and what you give up by turning it off. ## The default, and why The container runs `privileged=yes` unless you pass `--privileged=false` to `install` or `upgrade`, which recreates the container. It is a boolean flag, so it takes `=false`; a separate `false` argument is not read as its value. The setting exists on RouterOS 7.24 and later. Reading the device's internal state is what mikroscope is for, and privileged is what makes the root-only kernel files readable. An ordinary RouterOS container is placed in a user namespace where its root maps to host uid 32768, so `/proc/slabinfo` and `/dev/kmsg` come back `EACCES`. `privileged=yes` drops that user namespace. It is still a real grant of privilege, which is why `plan` and `install --dry-run` print it with the rest of the container's settings before anything is written. ## What it adds Found readable on the RB5009 (RouterOS 7.24.2, kernel 5.6.3) on 2026-09-12, and read by the agent except where the table says otherwise: | Source | What it gives | Where it shows | | ------------------------------ | -------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------ | | `/dev/kmsg` | the kernel ring buffer as timestamped events, naming the router's real interfaces | `mikroscope_kmsg_records_total{level}`, and Loki | | `/proc/slabinfo` | the global slab caches: `nf_conntrack` (the router's real connection count), `skbuff_*`, `TCP`/`UDP` sockets, `kmalloc-1k`/`-2k` | `mikroscope_slab_active_objects{cache}` | | `/sys/class/mtd` ECC counters | `corrected_bits` and `ecc_failures` per NAND partition | `mikroscope_mtd_ecc_corrected_bits_total`, `mikroscope_mtd_ecc_failures_total` | | the PMU, via `perf_event_open` | cycles, instructions, cache references and misses, branch misses, bus cycles, per core, system-wide | `mikroscope_perf_events_total{counter,cpu}` | | `/proc/pagetypeinfo` | readable, but the agent does not read it | nowhere | The PMU needs privileged for a different reason from the files: its counters are opened system-wide (`pid = -1`), which takes `CAP_PERFMON` or `CAP_SYS_ADMIN` against the host. `perf_event_paranoid` reads 2 on the reference device and does not block a privileged container. What the PMU shows that no tick counter can is on [the resolution floor](/mikroscope/limits/). The kernel log is read without blocking and capped at 64 records per tick. It is opened at the end of the buffer, so a boot-time backlog is never replayed as if it had just happened. `mikroscope_kmsg_dropped_total` counts loss events, not records: one per tick that hit the 64-record cap (that tick's one extra read is discarded, and the rest of the backlog is read on later ticks), and one per kernel ring overrun, which can stand for many records. While it is non-zero, the per-severity count under-counts. Whether this deployment got them is not left to inference. `/capabilities` carries `"privileged": true` only when both `/proc/slabinfo` and `/dev/kmsg` opened, and `mikroscope_device_info{privileged="true"}` says the same on `/metrics` and in every sink's device-info stream. Without privileged, the slab, PMU and MTD families are absent, not zero. The kernel-log family appears only once a record has been seen, so its absence alone cannot tell an unprivileged deployment from a quiet kernel; the `privileged` flag can. ## What it does not add It adds **no** network access and **no** view of RouterOS's processes. Privileged drops the user namespace and leaves the network and PID namespaces in place: Measured on RB5009UG+S+ · 4 × 1.4 GHz Cortex-A72 · RouterOS 7.24.2 · 2026-09-12 · `privileged=yes` does not change the network namespace So per-interface counters still come from the RouterOS API, and per-process CPU is out of reach even with the host's `/proc` mounted into the container. Both are measured on [the router's CPU, the container's network](/mikroscope/limits/namespaces/). It adds no extra capabilities either: an unprivileged container already holds all 38. What changes is the user namespace those capabilities are confined to, not the set. And it cannot give you more sensors than the board has. On the RB5009, `/sys/class/hwmon` is empty even privileged. The two thermal zones, `cpu-thermal` and `soc-thermal`, are the entire sensor set of the base model, and both are readable without privileged: there is no voltage, current or fan reading to be had. RouterOS's own `/system/health` on that board reports exactly one sensor, `cpu-temperature`, which is the `soc-thermal` zone truncated to whole degrees: a mean offset of +0.55 °C over the 8 minutes where both series existed (2026-09-14). On a board that does have voltage, current or fan sensors the API still adds them. > **True of this device, not of yours** > > The sensor set, the capability count and the uid mapping were read on one RB5009 on RouterOS > 7.24.2. A board with hwmon sensors, or a later RouterOS that builds containers differently, has > not been checked. ## Running without it `--privileged=false` keeps everything that is readable from an ordinary container: every global `/proc` file in the samples, the thermal zones, `scaling_cur_freq`, `/proc/yaffs`, `/proc/buddyinfo`, `/proc/diskstats`, and the agent's own cost. What goes: - The kernel log. The [layer-2 loop](/mikroscope/playbooks/loop/) this project found on its own reference router was visible only there. - The router's connection count from the slab cache. The RouterOS API's `count-only` table scan is the remaining source, which the collector runs only when `--conntrack-every` is set. - The NAND ECC counters. The YAFFS wear counters remain. - The PMU, and with it everything beneath the 10 ms tick. > **Privileged is not a mount** > > A privileged container with the host's `/` mounted reads the whole RouterOS configuration, secrets > included (tested on the RB5009 on 2026-09-15). The installer does not mount any host path into the > agent's container, and nothing here needs one. ## See also - [The router's CPU, the container's network](/mikroscope/limits/namespaces/): the two namespaces privileged leaves in place, file by file. - [What runs where](/mikroscope/security/): the agent's container and what it can reach, from the security side. - [Conntrack without the API](/mikroscope/playbooks/conntrack/): the slab count privileged makes readable, and how to check it. - [Flash wear](/mikroscope/playbooks/flash-wear/): the YAFFS counters that need no privilege and the ECC counters that do.