Alibabacloud Sysom Diagnosis

Use when troubleshooting Linux server performance or stability issues — CPU saturation, high load, scheduling delay, memory pressure, OOM events, high RSS, page cache / shared memory growth, memory cgroup residue, Java heap issues, disk IO saturation or latency, packet loss, network jitter, or a server that is slow, stuck, or unstable. Performs diagnosis and surfaces recommendations; does not apply fixes automatically.

Use SysOM CLI and backend envelopes as the diagnosis source of truth. This Skill replaces the older SysOM diagnosis Skill and is the single entry point for SysOM ECS performance and stability diagnosis.

Immediate Route

When the user reports a symptom and has not provided fresh SysOM envelope output, run the matching SysOM command from Domain Routing below before ad hoc Linux inspection or manual probing. Then follow the returned agent.summary, agent.findings[].detail/category, and agent.next_steps[]. Raw Linux commands are bounded fallbacks only when a SysOM command is unavailable, outputs contradict each other, or a required entity remains missing after the focused SysOM command.

Credential Security

Never print, echo, or ask for AccessKey ID or AccessKey Secret values. Remote commands perform their own authentication checks. If a command returns an authentication or permission error, explain the error and point the user to references/ram-policies.md; credential setup must happen outside the conversation.

CLI Setup

Check whether the CLI is available:

command -v sysom-osops

If it is missing, install it:

curl -fsSL --connect-timeout 1000 https://sysom-prd-cn-hangzhou.oss-cn-hangzhou.aliyuncs.com/sysom_prd/skill_cli/install.sh | sudo bash

Then verify only the binary:

command -v sysom-osops

Core Workflow

1. Classify the user's symptom into one SysOM domain: memory, IO, load/CPU, network, or Java memory.
2. Run the smallest SysOM command that matches that domain. Prefer a local memory classify for unclear memory symptoms; for other domains, use the matching documented remote action.
3. Read only the default envelope fields: ok, error, command, and agent.
4. Build the answer from agent.summary, agent.findings[].detail, agent.findings[].category, and agent.next_steps[]. Keep evidence qualifiers that change interpretation, including currentness, unavailable direct signals, fallback evidence, and remediation preconditions.
5. If the root cause, key entities, evidence strength, and safe next action are already visible, stop and answer. Run one targeted follow-up only when a required entity is missing or the command explicitly recommends it.

When classify returns a command in agent.next_steps[] and no root-cause finding already contains enough evidence to answer, run the first command next. Do not replace an Agent-visible SysOM next step with manual shell probing. Raw Linux checks are bounded fallbacks after the SysOM next step succeeds, fails, or times out.

Use the documented commands exactly as shown by default. Do not add raw, debug, or backend evidence expansion flags unless the user explicitly asks for that view.

Final answers should name evidence, root cause, owner/scope, and operational action targets. Do not add shell snippets for verification or remediation unless the user explicitly asks for commands. Prefer phrases such as "review dependency and disable or upgrade the leaking component in a change window" over raw module, cgroup, sysctl, cache-drop, or process-kill commands. Do not include command-looking inline snippets such as module inspection/removal, memory summary commands, cgroup file writes, cache-drop controls, sysctl changes, or process-kill commands as default final-answer steps.

The agent view must be self-contained for diagnosis. Structured evidence is a backend/UI view and must not be treated as the default Agent source for required entities.

Domain Routing

User symptom	First route
Unclear memory issue, OOM, high RSS, file cache, shmem/tmpfs, memory cgroup, socket memory, kernel memory	sysom-osops memory classify
Java heap, GC, or JVM memory issue	sysom-osops memory javamem when Java is explicit; otherwise start with memory classify
Slow disk, high iowait, disk latency, blocked IO	sysom-osops io iofsstat, then io iodiagnose if the overview points to slow IO
High load, runqueue backlog, task stuck waiting for CPU	sysom-osops load loadtask or load delay based on the visible symptom
Packet loss, retransmits, network timeout, jitter	sysom-osops net packetdrop for loss/drop symptoms; net netjitter for latency fluctuation

For command parameters, read references/deep-actions.md and references/parameter-guide.md. For OS and region support, read references/supported-environments.md. These references are Skill material; do not use remote target file tools to open .claude/skills paths on the diagnosed host.

Memory Routing

Memory follows the same Core Workflow and Follow-up Rules as every domain: start from sysom-osops memory classify, then pick the next action from visible output or agent.next_steps[]. For choosing among memory deep actions or checking which entity is still missing, load references/memory-triage.md (parallel to references/non-memory-triage.md for other domains).

Choose the next memory action from visible SysOM output. Do not infer a memory mechanism from symptom wording alone.

Envelope Contract

Default command output is the Agent contract:

{
  "ok": true,
  "command": "sysom-osops memory classify",
  "agent": {
    "status": "warning",
    "summary": "Concise diagnosis summary.",
    "findings": [
      {
        "severity": "high",
        "title": "Short finding title",
        "detail": "Root cause, key entities, and evidence summary.",
        "category": "root_cause"
      }
    ],
    "next_steps": [
      {
        "kind": "command",
        "label": "Run focused deep diagnosis",
        "command": "sysom-osops memory oom",
        "reason": "The missing entity this command can fill."
      }
    ]
  }
}

agent.findings[] may contain only severity, title, detail, and category. Required entities such as PID, cgroup, service, file path, OOM victim, limit/current, residue, holder, or cleanup target must be written in agent.summary or agent.findings[].detail.

Follow-up Rules

• Prefer category=root_cause, then highest severity, then the finding that best matches the user's reported symptom.
• Treat root_cause as stop-ready when visible detail contains the entities needed to explain the symptom and a safe next action.
• Treat agent.next_steps[] as a priority plan, not a checklist.
• Run another SysOM command only when it can fill a named missing entity or change remediation.
• Preserve visible qualifiers that affect interpretation, such as current versus historical evidence, unavailable direct signals, fallback evidence used to close currentness, and safety preconditions for remediation.
• When a finding uses fallback evidence because a direct signal is unavailable, state both parts in the final answer. Do not reduce the conclusion to the fallback metric alone.
• After a focused SysOM command closes a root cause, answer from it. Do not run extra commands to make the report comprehensive, and do not chase earlier classify anomalies or observations unless they share the same entity and expose a named evidence gap.
• Do not call backend-only collectors or private helper commands directly.
• Do not re-check a PID, cgroup, file, limit, or event that SysOM already named in summary or detail.
• After a SysOM deep command returns category=root_cause with the required entities visible, answer from that envelope. Raw Linux checks are only for contradictions, command errors, or a clearly missing entity.
• In the final answer, do not turn already-closed entities into extra raw Linux verification commands. Express remediation as dependency-aware action targets and change-window plans unless the envelope itself provides an executable safe next step.
• Avoid executable shell snippets in the final answer. If a command is useful only for post-change verification, name the SysOM check or metric to re-run instead of raw Linux commands.
• This includes inline command names for module inspection/removal, memory summary commands, cgroup file writes, cache-drop controls, sysctl changes, and process-kill actions; describe the dependency gate and operational action target in prose.
• Pivot across domains when the current envelope does not explain the reported symptom and another SysOM domain names a stronger root cause.
• During diagnosis, do not execute remediation commands that change target state, such as killing processes, removing files, changing sysctl values, or writing to cache-drop controls. Present those as recommendations unless the user explicitly asks you to perform the repair.
• For non-memory findings, keep the same rule: one focused deep command, then answer when the required entities are visible.

Error Handling

error.code	Action
Sysom.TargetRequired	Ask for instance ID and region, or explain ECS metadata auto-detection requirements
Sysom.FallbackClassify	Present the local classify result and continue only if a focused next step is available
Sysom.PermissionDenied	Use references/ram-policies.md to explain required RAM permissions
Sysom.AuthenticationFailure	Ask the user to configure credentials outside this session
Sysom.InvalidParameter	Ask the user to correct the instance, region, or command parameter
Sysom.DiagnosisVersionNotSupported	Explain that the target instance diagnosis components need an update
Sysom.DiagnosisJsonParseFailed	Retry once only when the user still needs the same evidence
Sysom.PollError	Retry the same focused action once when the missing evidence is still required

References

Reference	Use when
references/classify-output-guide.md	Reading local memory classify output
references/memory-triage.md	Choosing a memory deep action or checking memory entity completeness
references/non-memory-triage.md	Routing IO, load/CPU, network, and Java diagnosis
references/deep-actions.md	Looking up SysOM commands by domain
references/parameter-guide.md	Validating command parameters
references/report-interpretation.md	Interpreting envelope fields and answer shape
references/ram-policies.md	Explaining RAM permissions
references/supported-environments.md	Checking OS, architecture, and region support