ci-pipeline-debugging

name	ci-pipeline-debugging
description	Use when a Tekton build pipeline fails, when you need to understand task ordering or resource requirements, or when debugging security scan failures. Covers PR and push pipeline differences, the fetch-db-data step, and all security scan tasks.

CI Pipeline Debugging

Overview

This repo has two Tekton PipelineRun definitions in .tekton/: one for pull requests and one for pushes to main. Both are hermetic builds using trusted artifacts (OCI TA) with Cachi2 prefetching. The most critical and failure-prone step is fetch-db-data, which downloads the Clair vulnerability database and needs 16-32 GiB of memory.

When to Use

• A Tekton pipeline task failed and you need to understand what it does
• You need to understand the task execution order
• The fetch-db-data step is failing (OOM, timeout, network)
• A security scan is blocking the pipeline
• You need to understand PR vs push pipeline differences

Task Execution Order

init
  └─ clone-repository
       └─ fetch-db-data (non-hermetic, downloads matcher.db)
            └─ prefetch-dependencies (RPMs + generic artifacts via Cachi2)
                 └─ build-container (buildah, hermetic)
                      └─ build-image-index
                           ├─ clair-scan
                           ├─ clamav-scan
                           ├─ sast-snyk-check
                           ├─ sast-shell-check
                           ├─ sast-unicode-check
                           ├─ coverity-availability-check → sast-coverity-check
                           ├─ ecosystem-cert-preflight-checks
                           ├─ deprecated-base-image-check
                           ├─ rpms-signature-scan
                           ├─ apply-tags
                           ├─ push-dockerfile
                           └─ build-source-image (push only)
finally:
  └─ show-sbom

PR vs Push Pipeline Differences

Aspect	PR Pipeline	Push Pipeline
File	.tekton/clair-in-ci-db-hermetic-pull-request.yaml	.tekton/clair-in-ci-db-hermetic-push.yaml
Trigger	event == "pull_request" && target_branch == "main"	event == "push" && target_branch == "main"
Image tag	on-pr-{{revision}}	{{revision}}
Image expiry	5 days	None (permanent)
Cancel in-progress	Yes	No
Max kept runs	3	3
Source image build	No	Yes (when enabled)
Pipeline timeout	2 hours	2 hours

fetch-db-data Step (Most Common Failure Point)

This step downloads the latest Clair vulnerability database. It is the most resource-intensive and failure-prone task.

Property	Value
Task	run-script-oci-ta
Runner image	quay.io/projectquay/clair-action:v0.0.15
Command	DB_PATH=matcher.db /bin/clair-action --level info update
Hermetic	No (needs network access to download DB)
CPU request/limit	2 / 4 cores
Memory request/limit	16 GiB / 32 GiB
Timeout	2 hours

The output artifact (SCRIPT_ARTIFACT) is passed to prefetch-dependencies, which means the matcher.db file is included in the source artifact chain and eventually available during the build-container step where the Dockerfile COPY matcher.db /tmp/matcher.db picks it up.

Resource Requirements

Most tasks request 10 GiB memory. Key allocations:

Task	Memory (request/limit)	Notes
fetch-db-data	16 GiB / 32 GiB	Database download + processing
build-container	10 GiB / 10 GiB	buildah image build
prefetch-dependencies	10 GiB / 10 GiB	Cachi2 RPM + generic artifact download
clair-scan	10 GiB / 10 GiB	Vulnerability scanning of built image
clamav-scan	10 GiB / 10 GiB	Antivirus scan

Security Scan Tasks

All scans run in parallel after build-image-index and can be skipped with skip-checks: "true":

Scan	Task Bundle	What It Checks
Clair	task-clair-scan:0.3	CVE vulnerabilities in container image
ClamAV	task-clamav-scan:0.3	Malware/virus scan
Snyk SAST	task-sast-snyk-check-oci-ta:0.4	Static analysis security testing
ShellCheck	task-sast-shell-check-oci-ta:0.1	Shell script security and quality
Unicode	task-sast-unicode-check-oci-ta:0.4	Homoglyph/trojan-source attacks
Coverity	task-sast-coverity-check-oci-ta:0.3	Deep static analysis (if available)
RPM signatures	task-rpms-signature-scan:0.2	Verifies RPM package signatures
Preflight	task-ecosystem-cert-preflight-checks:0.2	Red Hat certification checks
Deprecated image	task-deprecated-image-check:0.5	Base image deprecation warnings

Common Failures

Problem	Likely Cause	Fix
fetch-db-data OOM killed	Database processing exceeds memory	Check if clair-action version needs more memory; may need to increase limits
fetch-db-data timeout	Network slow or database very large	Retry; check clair-action upstream for issues
prefetch-dependencies fails	Lock files out of sync with rpms.in.yaml	Regenerate rpms.lock.yaml and artifacts.lock.yaml
build-container fails	Dockerfile error or missing prefetched deps	Check Dockerfile syntax; verify all deps are in lock files
clair-scan fails	High/critical CVEs found in built image	Review CVE report; update base image or add exceptions
rpms-signature-scan fails	Unsigned or incorrectly signed RPM	Verify RPM source and GPG key in artifacts.lock.yaml
Pipeline stuck at coverity	Coverity not available in tenant	Expected — coverity-availability-check gates it

Trusted Artifacts (OCI TA)

This pipeline uses OCI-based trusted artifacts instead of PVCs for sharing data between tasks:

• Source code is stored as OCI artifacts in the output image registry
• SOURCE_ARTIFACT results chain through: clone → fetch-db-data → prefetch → build
• CACHI2_ARTIFACT carries prefetched dependencies from prefetch → build
• Artifacts expire based on ociArtifactExpiresAfter (PR: 5 days, push: never)