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feat(vm): replace Firecracker with Cloud Hypervisor

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Migrate the entire VM layer from Firecracker to Cloud Hypervisor (CH).
CH provides native snapshot/restore via its HTTP API, eliminating the
need for custom UFFD handling, memfile processing, and snapshot header
management that Firecracker required.

Key changes:
- Remove fc.go, jailer.go (FC process management)
- Remove internal/uffd/ package (userfaultfd lazy page loading)
- Remove snapshot/header.go, mapping.go, memfile.go (FC snapshot format)
- Add ch.go (CH HTTP API client over Unix socket)
- Add process.go (CH process lifecycle with unshare+netns)
- Add chversion.go (CH version detection)
- Refactor sandbox manager: remove UFFD socket tracking, snapshot
  parent/diff chaining, FC-specific balloon logic; add crash watcher
- Simplify snapshot/local.go to CH's native snapshot format
- Update VM config: FirecrackerBin → VMMBin, new CH-specific fields
- Update envdclient, devicemapper, network for CH compatibility
This commit is contained in:
Rafeed M. Bhuiyan
2026-05-17 01:33:12 +06:00
parent c2dc382787
commit eaa6b8576d
25 changed files with 754 additions and 2267 deletions
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40
internal/envdclient/client.go
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@ -294,7 +294,7 @@ func (c *Client) ReadFile(ctx context.Context, path string) ([]byte, error) {
// PrepareSnapshot calls envd's POST /snapshot/prepare endpoint, which stops
// the port scanner/forwarder and marks active connections for post-restore
// cleanup before Firecracker freezes vCPUs.
// cleanup before the VMM freezes vCPUs.
//
// Best-effort: the caller should log a warning on error but not abort the pause.
func (c *Client) PrepareSnapshot(ctx context.Context) error {
@ -317,27 +317,33 @@ func (c *Client) PrepareSnapshot(ctx context.Context) error {
return nil
}
// PostInit calls envd's POST /init endpoint, which triggers a re-read of
// Firecracker MMDS metadata. This updates WRENN_SANDBOX_ID, WRENN_TEMPLATE_ID
// env vars and the corresponding files under /run/wrenn/ inside the guest.
// Must be called after snapshot restore so envd picks up the new sandbox's metadata.
// PostInit calls envd's POST /init endpoint to trigger post-boot or
// post-restore initialization. sandbox_id and template_id are passed
// so envd can set WRENN_SANDBOX_ID and WRENN_TEMPLATE_ID env vars.
func (c *Client) PostInit(ctx context.Context) error {
return c.PostInitWithDefaults(ctx, "", nil)
return c.PostInitWithDefaults(ctx, "", nil, "", "")
}
// PostInitWithDefaults calls envd's POST /init endpoint with optional default
// user and environment variables. These are applied to envd's defaults so all
// subsequent process executions use them.
func (c *Client) PostInitWithDefaults(ctx context.Context, defaultUser string, envVars map[string]string) error {
// user, environment variables, and sandbox metadata. These are applied to
// envd's defaults so all subsequent process executions use them.
func (c *Client) PostInitWithDefaults(ctx context.Context, defaultUser string, envVars map[string]string, sandboxID, templateID string) error {
payload := make(map[string]any)
if defaultUser != "" {
payload["defaultUser"] = defaultUser
}
if len(envVars) > 0 {
payload["envVars"] = envVars
}
if sandboxID != "" {
payload["sandbox_id"] = sandboxID
}
if templateID != "" {
payload["template_id"] = templateID
}
var body io.Reader
if defaultUser != "" || len(envVars) > 0 {
payload := make(map[string]any)
if defaultUser != "" {
payload["defaultUser"] = defaultUser
}
if len(envVars) > 0 {
payload["envVars"] = envVars
}
if len(payload) > 0 {
data, err := json.Marshal(payload)
if err != nil {
return fmt.Errorf("marshal init body: %w", err)