package-installation

name	package-installation
description	Guides writing remote package installation commands (apt-get, yum, dnf, zypper) in SCT code. Use when adding apt-get install/update, yum install, dnf install, or zypper install calls via remoter.run/remoter.sudo. Ensures timeouts, retries, and non-interactive flags are always present to prevent hangs in CI.

Package Installation Commands in SCT

Best practices for running package manager commands on remote nodes via remoter.run() / remoter.sudo().

Why This Matters

Remote package installation can hang indefinitely due to:

• Network timeouts to package repositories
• GPG keyserver unavailability
• dpkg lock contention from unattended-upgrades
• Interactive prompts when running non-interactively

A single hung apt-get call can block an entire SCT test for hours/days.

Mandatory Options by Package Manager

apt-get (Debian/Ubuntu)

Every apt-get call MUST include:

# For apt-get update:
self.remoter.sudo(
    "apt-get -o Acquire::http::Timeout=60 -o Acquire::Retries=3 update",
    ignore_status=True,
)

# For apt-get install:
self.remoter.sudo(
    "DEBIAN_FRONTEND=noninteractive apt-get install "
    "-o DPkg::Lock::Timeout=120 "
    "-o Acquire::http::Timeout=60 "
    "-o Acquire::Retries=3 "
    '-o Dpkg::Options::="--force-confold" '
    '-o Dpkg::Options::="--force-confdef" '
    "-y <package>",
)

Required options:

Option	Purpose
DEBIAN_FRONTEND=noninteractive	Prevents interactive prompts (install only)
-o Acquire::http::Timeout=60	60s timeout for HTTP downloads — prevents indefinite hangs
-o Acquire::Retries=3	Retry failed downloads 3 times
-o DPkg::Lock::Timeout=120	Wait up to 120s for dpkg lock (install only)
-o Dpkg::Options::="--force-confold"	Keep existing config files (install only)
-o Dpkg::Options::="--force-confdef"	Use default for new config files (install only)
-y	Assume yes to all prompts (install only)

yum / dnf (RHEL/CentOS/Fedora)

# yum/dnf have built-in timeouts (default 30s) but always use:
self.remoter.sudo("yum install -y <package>", retry=3)

# For long-running operations, add timeout to the remoter call:
self.remoter.sudo("yum install -y <package>", retry=3, timeout=600)

Required options:

Option	Purpose
-y	Non-interactive
retry=3 on remoter call	Retry on SSH/command failures
timeout=600 on remoter call	Prevent indefinite hangs (for large packages)

zypper (SLES)

self.remoter.sudo("zypper install -y <package>", retry=3)

Required options:

Option	Purpose
-y	Non-interactive
retry=3 on remoter call	Retry on failures

The install_package() Method

Prefer using BaseNode.install_package() from sdcm/cluster.py which already handles:

• Distro detection (apt vs yum vs zypper)
• Proper timeout/retry options
• @retrying decorator for transient failures
• Version pinning

# Preferred:
self.install_package("scylla-manager-agent")

# Only use raw remoter commands when install_package doesn't fit
# (e.g., shell scripts, multi-command pipelines)

Shell Script Blocks

When apt-get commands are embedded in shell scripts (via shell_script_cmd() or heredocs), the same options apply:

script = dedent("""
    sudo apt-get -o Acquire::http::Timeout=60 -o Acquire::Retries=3 update
    sudo apt-get -o Acquire::http::Timeout=60 -o Acquire::Retries=3 install -y docker.io
""")

GPG Key Fetching

Use BaseNode.fetch_apt_keys() which handles:

• Multiple HKP keyserver fallbacks
• HTTPS fallback
• Timeout on each attempt (--keyserver-options timeout=10)
• Raises NodeSetupFailed if all sources fail

Never write bare apt-key adv --recv-keys without timeout and fallback logic.

Anti-Patterns

# BAD: No timeout, will hang forever on network issues
self.remoter.sudo("apt-get update")
self.remoter.sudo("apt-get install -y foo")

# BAD: Missing DEBIAN_FRONTEND, may prompt
self.remoter.sudo("apt-get install -y foo")

# BAD: No Acquire timeout, download can hang
self.remoter.sudo("DEBIAN_FRONTEND=noninteractive apt-get install -y foo")

# BAD: ignore_status without retry — silently fails
self.remoter.sudo("apt-get update", ignore_status=True)

Checklist for Code Review

When reviewing code that adds package installation:

• Acquire::http::Timeout=60 present on all apt-get calls?
• Acquire::Retries=3 present on all apt-get calls?
• DEBIAN_FRONTEND=noninteractive on all apt-get install calls?
• -y flag on all install commands (apt, yum, zypper)?
• DPkg::Lock::Timeout on apt-get install calls?
• retry=N on remoter call for yum/zypper?
• No bare apt-key adv without timeout/fallback?
• Prefer install_package() over raw commands?