sandbox: set the dns for the sandbox

The rust agent had supported to set the guest dns
server in start sandbox request, thus add the dns
in the runtime side.

Fixes:#6286

Signed-off-by: Fupan Li <fupan.lfp@antgroup.com>

src/libs/kata-types/src/config/default.rs

@@ -42,6 +42,7 @@ pub const MIN_SHARED_9PFS_SIZE_MB: u32 = 4 * 1024;
 pub const MAX_SHARED_9PFS_SIZE_MB: u32 = 8 * 1024 * 1024;
 
 pub const DEFAULT_GUEST_HOOK_PATH: &str = "/opt/kata/hooks";
+pub const DEFAULT_GUEST_DNS_FILE: &str = "/etc/resolv.conf";
 
 pub const DEFAULT_GUEST_VCPUS: u32 = 1;
 

src/runtime-rs/crates/runtimes/common/src/sandbox.rs

@@ -9,7 +9,7 @@ use async_trait::async_trait;
 
 #[async_trait]
 pub trait Sandbox: Send + Sync {
-    async fn start(&self, netns: Option<String>) -> Result<()>;
+    async fn start(&self, netns: Option<String>, dns: Vec<String>) -> Result<()>;
     async fn stop(&self) -> Result<()>;
     async fn cleanup(&self, container_id: &str) -> Result<()>;
     async fn shutdown(&self) -> Result<()>;

src/runtime-rs/crates/runtimes/src/manager.rs

@@ -15,11 +15,14 @@ use common::{
     RuntimeHandler, RuntimeInstance, Sandbox,
 };
 use hypervisor::Param;
-use kata_types::{annotations::Annotation, config::TomlConfig};
+use kata_types::{
+    annotations::Annotation, config::default::DEFAULT_GUEST_DNS_FILE, config::TomlConfig,
+};
 #[cfg(feature = "linux")]
 use linux_container::LinuxContainer;
 use persist::sandbox_persist::Persist;
 use shim_interface::shim_mgmt::ERR_NO_SHIM_SERVER;
+use tokio::fs;
 use tokio::sync::{mpsc::Sender, RwLock};
 #[cfg(feature = "virt")]
 use virt_container::{
@@ -48,6 +51,7 @@ impl RuntimeHandlerManagerInner {
     async fn init_runtime_handler(
         &mut self,
         netns: Option<String>,
+        dns: Vec<String>,
         config: Arc<TomlConfig>,
     ) -> Result<()> {
         info!(sl!(), "new runtime handler {}", &config.runtime.name);
@@ -70,7 +74,7 @@ impl RuntimeHandlerManagerInner {
         // start sandbox
         runtime_instance
             .sandbox
-            .start(netns)
+            .start(netns, dns)
             .await
             .context("start sandbox")?;
         self.runtime_instance = Some(Arc::new(runtime_instance));
@@ -83,6 +87,8 @@ impl RuntimeHandlerManagerInner {
             return Ok(());
         }
 
+        let mut dns: Vec<String> = vec![];
+
         #[cfg(feature = "linux")]
         LinuxContainer::init().context("init linux container")?;
         #[cfg(feature = "wasm")]
@@ -107,8 +113,15 @@ impl RuntimeHandlerManagerInner {
             None
         };
 
+        for m in &spec.mounts {
+            if m.destination == DEFAULT_GUEST_DNS_FILE {
+                let contents = fs::read_to_string(&m.source).await?;
+                dns = contents.split('\n').map(|e| e.to_string()).collect();
+            }
+        }
+
         let config = load_config(spec, options).context("load config")?;
-        self.init_runtime_handler(netns, Arc::new(config))
+        self.init_runtime_handler(netns, dns, Arc::new(config))
             .await
             .context("init runtime handler")?;
 

src/runtime-rs/crates/runtimes/virt_container/src/sandbox.rs

@@ -123,7 +123,7 @@ impl VirtSandbox {
 
 #[async_trait]
 impl Sandbox for VirtSandbox {
-    async fn start(&self, netns: Option<String>) -> Result<()> {
+    async fn start(&self, netns: Option<String>, dns: Vec<String>) -> Result<()> {
         let id = &self.sid;
 
         // if sandbox running, return
@@ -170,7 +170,7 @@ impl Sandbox for VirtSandbox {
         let kernel_modules = KernelModule::set_kernel_modules(agent_config.kernel_modules)?;
         let req = agent::CreateSandboxRequest {
             hostname: "".to_string(),
-            dns: vec![],
+            dns,
             storages: self
                 .resource_manager
                 .get_storage_for_sandbox()