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consul: probe consul namespace feature before using namespace api
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This PR changes Nomad's wrapper around the Consul NamespaceAPI so that
it will detect if the Consul Namespaces feature is enabled before making
a request to the Namespaces API. Namespaces are not enabled in Consul OSS,
and require a suitable license to be used with Consul ENT.

Previously Nomad would check for a 404 status code when makeing a request
to the Namespaces API to "detect" if Consul OSS was being used. This does
not work for Consul ENT with Namespaces disabled, which returns a 500.

Now we avoid requesting the namespace API altogether if Consul is detected
to be the OSS sku, or if the Namespaces feature is not licensed. Since
Consul can be upgraded from OSS to ENT, or a new license applied, we cache
the value for 1 minute, refreshing on demand if expired.

Fixes hashicorp/nomad-enterprise#575

Note that the ticket originally describes using attributes from #10688.
This turns out not to be possible due to a chicken-egg situation between
bootstrapping the agent and setting up the consul client. Also fun: the
Consul fingerprinter creates its own Consul client, because there is no
[currently] no way to pass the agent's client through the fingerprint factory.
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@shoenig
shoenig committed Jun 7, 2021
1 parent bdf2555 commit b1b003d
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Showing 16 changed files with 451 additions and 123 deletions.
1 change: 1 addition & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@ BUG FIXES:
* api: Fixed event stream connection initialization when there are no events to send [[GH-10637](https://github.com/hashicorp/nomad/issues/10637)]
* cli: Fixed a bug where `quota status` and `namespace status` commands may panic if the CLI targets a pre-1.1.0 cluster [[GH-10620](https://github.com/hashicorp/nomad/pull/10620)]
* cli: Fixed a bug where `alloc exec` may fail with "unexpected EOF" without returning the exit code after a command [[GH-10657](https://github.com/hashicorp/nomad/issues/10657)]
* consul: Fixed a bug where consul namespace API would be queried even when consul namespaces were not enabled [[GH-10715](https://github.com/hashicorp/nomad/pull/10715)]
* csi: Fixed a bug where `mount_options` were not passed to CSI controller plugins for validation during volume creation and mounting. [[GH-10643](https://github.com/hashicorp/nomad/issues/10643)]
* csi: Fixed a bug where `capability` blocks were not passed to CSI controller plugins for validation for `nomad volume register` commands. [[GH-10703](https://github.com/hashicorp/nomad/issues/10703)]
* drivers/exec: Fixed a bug where `exec` and `java` tasks inherit the Nomad agent's `oom_score_adj` value [[GH-10698](https://github.com/hashicorp/nomad/issues/10698)]
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2 changes: 1 addition & 1 deletion client/allocrunner/groupservice_hook_test.go
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Expand Up @@ -238,7 +238,7 @@ func TestGroupServiceHook_Update08Alloc(t *testing.T) {
consulConfig.Address = testconsul.HTTPAddr
consulClient, err := consulapi.NewClient(consulConfig)
require.NoError(t, err)
namespacesClient := agentconsul.NewNamespacesClient(consulClient.Namespaces())
namespacesClient := agentconsul.NewNamespacesClient(consulClient.Namespaces(), consulClient.Agent())

serviceClient := agentconsul.NewServiceClient(consulClient.Agent(), namespacesClient, testlog.HCLogger(t), true)

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74 changes: 18 additions & 56 deletions client/fingerprint/consul.go
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Original file line number Diff line number Diff line change
Expand Up @@ -3,12 +3,11 @@ package fingerprint
import (
"fmt"
"strconv"
"strings"
"time"

consul "github.com/hashicorp/consul/api"
consulapi "github.com/hashicorp/consul/api"
log "github.com/hashicorp/go-hclog"
"github.com/hashicorp/go-version"
agentconsul "github.com/hashicorp/nomad/command/agent/consul"
)

const (
Expand All @@ -19,17 +18,14 @@ const (
// ConsulFingerprint is used to fingerprint for Consul
type ConsulFingerprint struct {
logger log.Logger
client *consul.Client
client *consulapi.Client
lastState string
extractors map[string]consulExtractor
}

// consulInfo aliases the type returned from the Consul agent self endpoint.
type consulInfo = map[string]map[string]interface{}

// consulExtractor is used to parse out one attribute from consulInfo. Returns
// the value of the attribute, and whether the attribute exists.
type consulExtractor func(consulInfo) (string, bool)
type consulExtractor func(agentconsul.Self) (string, bool)

// NewConsulFingerprint is used to create a Consul fingerprint
func NewConsulFingerprint(logger log.Logger) Fingerprint {
Expand Down Expand Up @@ -95,7 +91,7 @@ func (f *ConsulFingerprint) initialize(req *FingerprintRequest) error {
return fmt.Errorf("failed to initialize Consul client config: %v", err)
}

f.client, err = consul.NewClient(consulConfig)
f.client, err = consulapi.NewClient(consulConfig)
if err != nil {
return fmt.Errorf("failed to initialize Consul client: %s", err)
}
Expand All @@ -117,7 +113,7 @@ func (f *ConsulFingerprint) initialize(req *FingerprintRequest) error {
return nil
}

func (f *ConsulFingerprint) query(resp *FingerprintResponse) consulInfo {
func (f *ConsulFingerprint) query(resp *FingerprintResponse) agentconsul.Self {
// We'll try to detect consul by making a query to to the agent's self API.
// If we can't hit this URL consul is probably not running on this machine.
info, err := f.client.Agent().Self()
Expand All @@ -144,48 +140,36 @@ func (f *ConsulFingerprint) link(resp *FingerprintResponse) {
}
}

func (f *ConsulFingerprint) server(info consulInfo) (string, bool) {
func (f *ConsulFingerprint) server(info agentconsul.Self) (string, bool) {
s, ok := info["Config"]["Server"].(bool)
return strconv.FormatBool(s), ok
}

func (f *ConsulFingerprint) version(info consulInfo) (string, bool) {
func (f *ConsulFingerprint) version(info agentconsul.Self) (string, bool) {
v, ok := info["Config"]["Version"].(string)
return v, ok
}

func (f *ConsulFingerprint) sku(info consulInfo) (string, bool) {
v, ok := info["Config"]["Version"].(string)
if !ok {
return "", ok
}

ver, vErr := version.NewVersion(v)
if vErr != nil {
return "", false
}
if strings.Contains(ver.Metadata(), "ent") {
return "ent", true
}
return "oss", true
func (f *ConsulFingerprint) sku(info agentconsul.Self) (string, bool) {
return agentconsul.SKU(info)
}

func (f *ConsulFingerprint) revision(info consulInfo) (string, bool) {
func (f *ConsulFingerprint) revision(info agentconsul.Self) (string, bool) {
r, ok := info["Config"]["Revision"].(string)
return r, ok
}

func (f *ConsulFingerprint) name(info consulInfo) (string, bool) {
func (f *ConsulFingerprint) name(info agentconsul.Self) (string, bool) {
n, ok := info["Config"]["NodeName"].(string)
return n, ok
}

func (f *ConsulFingerprint) dc(info consulInfo) (string, bool) {
func (f *ConsulFingerprint) dc(info agentconsul.Self) (string, bool) {
d, ok := info["Config"]["Datacenter"].(string)
return d, ok
}

func (f *ConsulFingerprint) segment(info consulInfo) (string, bool) {
func (f *ConsulFingerprint) segment(info agentconsul.Self) (string, bool) {
tags, tagsOK := info["Member"]["Tags"].(map[string]interface{})
if !tagsOK {
return "", false
Expand All @@ -194,38 +178,16 @@ func (f *ConsulFingerprint) segment(info consulInfo) (string, bool) {
return s, ok
}

func (f *ConsulFingerprint) connect(info consulInfo) (string, bool) {
func (f *ConsulFingerprint) connect(info agentconsul.Self) (string, bool) {
c, ok := info["DebugConfig"]["ConnectEnabled"].(bool)
return strconv.FormatBool(c), ok
}

func (f *ConsulFingerprint) grpc(info consulInfo) (string, bool) {
func (f *ConsulFingerprint) grpc(info agentconsul.Self) (string, bool) {
p, ok := info["DebugConfig"]["GRPCPort"].(float64)
return fmt.Sprintf("%d", int(p)), ok
}

func (f *ConsulFingerprint) namespaces(info consulInfo) (string, bool) {
return f.feature("Namespaces", info)
}

// possible values as of v1.9.5+ent:
// Automated Backups, Automated Upgrades, Enhanced Read Scalability,
// Network Segments, Redundancy Zone, Advanced Network Federation,
// Namespaces, SSO, Audit Logging
func (f *ConsulFingerprint) feature(name string, info consulInfo) (string, bool) {
lic, licOK := info["Stats"]["license"].(map[string]interface{})
if !licOK {
return "", false
}

features, exists := lic["features"].(string)
if !exists {
return "", false
}

if !strings.Contains(features, name) {
return "", false
}

return "true", true
func (f *ConsulFingerprint) namespaces(info agentconsul.Self) (string, bool) {
return agentconsul.Namespaces(info)
}

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