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CRI: An empty DNSConfig != unspecified

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If we find that DNSConfig is provided and empty (not nil), we should not
replace it with the host's resolv.conf.

Also adds tests.

Signed-off-by: Tim Hockin <thockin@google.com>
This commit is contained in:
Tim Hockin 2024-02-01 13:22:49 -08:00
parent ac54047344
commit 6e365e9250
No known key found for this signature in database
2 changed files with 85 additions and 13 deletions
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22
pkg/cri/server/podsandbox/sandbox_run_linux.go
View File

@ -268,25 +268,21 @@ func (c *Controller) setupSandboxFiles(id string, config *runtime.PodSandboxConf
}
// Set DNS options. Maintain a resolv.conf for the sandbox.
var err error
resolvContent := ""
resolvPath := c.getResolvPath(id)
if dnsConfig := config.GetDnsConfig(); dnsConfig != nil {
resolvContent, err = parseDNSOptions(dnsConfig.Servers, dnsConfig.Searches, dnsConfig.Options)
resolvContent, err := parseDNSOptions(dnsConfig.Servers, dnsConfig.Searches, dnsConfig.Options)
if err != nil {
return fmt.Errorf("failed to parse sandbox DNSConfig %+v: %w", dnsConfig, err)
}
}
resolvPath := c.getResolvPath(id)
if resolvContent == "" {
// copy host's resolv.conf to resolvPath
err = c.os.CopyFile(resolvConfPath, resolvPath, 0644)
if err != nil {
return fmt.Errorf("failed to copy host's resolv.conf to %q: %w", resolvPath, err)
if err := c.os.WriteFile(resolvPath, []byte(resolvContent), 0644); err != nil {
return fmt.Errorf("failed to write resolv content to %q: %w", resolvPath, err)
}
} else {
err = c.os.WriteFile(resolvPath, []byte(resolvContent), 0644)
if err != nil {
return fmt.Errorf("failed to write resolv content to %q: %w", resolvPath, err)
// The DnsConfig was nil - we interpret that to mean "use the global
// default", which is dubious but backwards-compatible.
if err := c.os.CopyFile(resolvConfPath, resolvPath, 0644); err != nil {
return fmt.Errorf("failed to copy host's resolv.conf to %q: %w", resolvPath, err)
}
}

76
pkg/cri/server/podsandbox/sandbox_run_linux_test.go
View File

@ -511,6 +511,82 @@ options timeout:1
},
},
},
{
desc: "should create empty /etc/resolv.conf if DNSOptions is empty",
dnsConfig: &runtime.DNSConfig{},
ipcMode: runtime.NamespaceMode_NODE,
expectedCalls: []ostesting.CalledDetail{
{
Name: "Hostname",
},
{
Name: "WriteFile",
Arguments: []interface{}{
filepath.Join(testRootDir, sandboxesDir, testID, "hostname"),
[]byte(realhostname + "\n"),
os.FileMode(0644),
},
},
{
Name: "CopyFile",
Arguments: []interface{}{
"/etc/hosts",
filepath.Join(testRootDir, sandboxesDir, testID, "hosts"),
os.FileMode(0644),
},
},
{
Name: "WriteFile",
Arguments: []interface{}{
filepath.Join(testRootDir, sandboxesDir, testID, "resolv.conf"),
[]byte{},
os.FileMode(0644),
},
},
{
Name: "Stat",
Arguments: []interface{}{"/dev/shm"},
},
},
},
{
desc: "should copy host /etc/resolv.conf if DNSOptions is not set",
dnsConfig: nil,
ipcMode: runtime.NamespaceMode_NODE,
expectedCalls: []ostesting.CalledDetail{
{
Name: "Hostname",
},
{
Name: "WriteFile",
Arguments: []interface{}{
filepath.Join(testRootDir, sandboxesDir, testID, "hostname"),
[]byte(realhostname + "\n"),
os.FileMode(0644),
},
},
{
Name: "CopyFile",
Arguments: []interface{}{
"/etc/hosts",
filepath.Join(testRootDir, sandboxesDir, testID, "hosts"),
os.FileMode(0644),
},
},
{
Name: "CopyFile",
Arguments: []interface{}{
filepath.Join("/etc/resolv.conf"),
filepath.Join(testRootDir, sandboxesDir, testID, "resolv.conf"),
os.FileMode(0644),
},
},
{
Name: "Stat",
Arguments: []interface{}{"/dev/shm"},
},
},
},
{
desc: "should create sandbox shm when ipc namespace mode is not NODE",
ipcMode: runtime.NamespaceMode_POD,