Adolfo Delorenzo
d900fa920e
Implement a lightweight cloud-init system for first-boot configuration: - Go parser for YAML config (hostname, network, KubeSolo settings) - Static/DHCP network modes with DNS override - KubeSolo extra flags and API server SAN configuration - Portainer Edge Agent and air-gapped deployment support - New init stage 45-cloud-init.sh runs before network/hostname stages - Stages 50/60 skip gracefully when cloud-init has already applied - Build script compiles static Linux/amd64 binary (~2.7 MB) - 17 unit tests covering parsing, validation, and example files - Full documentation at docs/cloud-init.md Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
81 lines
2.0 KiB
Go
81 lines
2.0 KiB
Go
package cloudinit
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import (
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"fmt"
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"log/slog"
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"os"
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"strings"
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)
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// ApplyHostname sets the system hostname and updates /etc/hostname and /etc/hosts.
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func ApplyHostname(cfg *Config) error {
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hostname := cfg.Hostname
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if hostname == "" {
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slog.Info("no hostname in cloud-init, skipping")
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return nil
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}
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// Set the running hostname
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if err := os.WriteFile("/proc/sys/kernel/hostname", []byte(hostname), 0o644); err != nil {
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// Fallback: use the hostname command
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if err := run("hostname", hostname); err != nil {
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return fmt.Errorf("setting hostname: %w", err)
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}
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}
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// Write /etc/hostname
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if err := os.WriteFile("/etc/hostname", []byte(hostname+"\n"), 0o644); err != nil {
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return fmt.Errorf("writing /etc/hostname: %w", err)
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}
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// Ensure hostname is in /etc/hosts
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if err := ensureHostsEntry(hostname); err != nil {
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return fmt.Errorf("updating /etc/hosts: %w", err)
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}
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slog.Info("hostname set", "hostname", hostname)
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return nil
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}
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// SaveHostname writes the hostname to the persistent data partition so it
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// survives reboots (even without cloud-init on next boot).
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func SaveHostname(cfg *Config, destDir string) error {
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if cfg.Hostname == "" {
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return nil
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}
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if err := os.MkdirAll(destDir, 0o755); err != nil {
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return fmt.Errorf("creating hostname dir: %w", err)
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}
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dest := destDir + "/hostname"
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if err := os.WriteFile(dest, []byte(cfg.Hostname+"\n"), 0o644); err != nil {
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return fmt.Errorf("writing persistent hostname: %w", err)
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}
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slog.Info("hostname saved", "path", dest)
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return nil
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}
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func ensureHostsEntry(hostname string) error {
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data, err := os.ReadFile("/etc/hosts")
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if err != nil && !os.IsNotExist(err) {
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return err
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}
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content := string(data)
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entry := "127.0.0.1 " + hostname
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// Check if already present
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for _, line := range strings.Split(content, "\n") {
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if strings.Contains(line, hostname) {
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return nil
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}
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}
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// Append
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if !strings.HasSuffix(content, "\n") && content != "" {
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content += "\n"
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}
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content += entry + "\n"
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return os.WriteFile("/etc/hosts", []byte(content), 0o644)
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}
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