The Operations Service¶
The peer and the orderer host an HTTP server that offers a RESTful “operations” API. This API is unrelated to the Fabric network services and is intended to be used by operators, not administrators or “users” of the network.
The API exposes the following capabilities:
Log level management
Health checks
Prometheus target for operational metrics (when configured)
Endpoint for retrieving version information
Configuring the Operations Service¶
The operations service requires two basic pieces of configuration:
The address and port to listen on.
The TLS certificates and keys to use for authentication and encryption. Note, these certificates should be generated by a separate and dedicated CA. Do not use a CA that has generated certificates for any organizations in any channels.
Peer¶
For each peer, the operations server can be configured in the operations
section of core.yaml
:
operations:
# host and port for the operations server
listenAddress: 127.0.0.1:9443
# TLS configuration for the operations endpoint
tls:
# TLS enabled
enabled: true
# path to PEM encoded server certificate for the operations server
cert:
file: tls/server.crt
# path to PEM encoded server key for the operations server
key:
file: tls/server.key
# most operations service endpoints require client authentication when TLS
# is enabled. clientAuthRequired requires client certificate authentication
# at the TLS layer to access all resources.
clientAuthRequired: false
# paths to PEM encoded ca certificates to trust for client authentication
clientRootCAs:
files: []
The listenAddress
key defines the host and port that the operation server
will listen on. If the server should listen on all addresses, the host portion
can be omitted.
The tls
section is used to indicate whether or not TLS is enabled for the
operations service, the location of the service’s certificate and private key,
and the locations of certificate authority root certificates that should be
trusted for client authentication. When enabled
is true, most of the operations
service endpoints require client authentication, therefore
clientRootCAs.files
must be set. When clientAuthRequired
is true
,
the TLS layer will require clients to provide a certificate for authentication
on every request. See Operations Security section below for more details.
Orderer¶
For each orderer, the operations server can be configured in the Operations
section of orderer.yaml
:
Operations:
# host and port for the operations server
ListenAddress: 127.0.0.1:8443
# TLS configuration for the operations endpoint
TLS:
# TLS enabled
Enabled: true
# PrivateKey: PEM-encoded tls key for the operations endpoint
PrivateKey: tls/server.key
# Certificate governs the file location of the server TLS certificate.
Certificate: tls/server.crt
# Paths to PEM encoded ca certificates to trust for client authentication
ClientRootCAs: []
# Most operations service endpoints require client authentication when TLS
# is enabled. ClientAuthRequired requires client certificate authentication
# at the TLS layer to access all resources.
ClientAuthRequired: false
The ListenAddress
key defines the host and port that the operations server
will listen on. If the server should listen on all addresses, the host portion
can be omitted.
The TLS
section is used to indicate whether or not TLS is enabled for the
operations service, the location of the service’s certificate and private key,
and the locations of certificate authority root certificates that should be
trusted for client authentication. When Enabled
is true, most of the operations
service endpoints require client authentication, therefore
RootCAs
must be set. When ClientAuthRequired
is true
,
the TLS layer will require clients to provide a certificate for authentication
on every request. See Operations Security section below for more details.
Operations Security¶
As the operations service is focused on operations and intentionally unrelated to the Fabric network, it does not use the Membership Services Provider for access control. Instead, the operations service relies entirely on mutual TLS with client certificate authentication.
When TLS is disabled, authorization is bypassed and any client that can connect to the operations endpoint will be able to use the API.
When TLS is enabled, a valid client certificate must be provided in order to
access the logging and metrics services. The health check and version services
only require a valid client certificate when clientAuthRequired
is enabled,
since these services are often used by network operators and only provide read-only information.
When clientAuthRequired
is enabled, the TLS layer will also require
a valid client certificate regardless of the resource being accessed.
Log Level Management¶
The operations service provides a /logspec
resource that operators can use to
manage the active logging spec for a peer or orderer. The resource is a
conventional REST resource and supports GET
and PUT
requests.
When a GET /logspec
request is received by the operations service, it will
respond with a JSON payload that contains the current logging specification:
{"spec":"info"}
When a PUT /logspec
request is received by the operations service, it will
read the body as a JSON payload. The payload must consist of a single attribute
named spec
.
{"spec":"chaincode=debug:info"}
If the spec is activated successfully, the service will respond with a 204 "No Content"
response. If an error occurs, the service will respond with a 400 "Bad Request"
and an error payload:
{"error":"error message"}
When TLS is enabled, a valid client certificate is required to use this
service regardless of whether clientAuthRequired
is set to true
at the TLS level.
Metrics¶
Some components of the Fabric peer and orderer expose metrics that can help provide insight into the behavior of the system. Operators and administrators can use this information to better understand how the system is performing over time.
Configuring Metrics¶
Fabric provides two ways to expose metrics: a pull model based on Prometheus and a push model based on StatsD.
Prometheus¶
A typical Prometheus deployment scrapes metrics by requesting them from an HTTP endpoint exposed by instrumented targets. As Prometheus is responsible for requesting the metrics, it is considered a pull system.
When configured, a Fabric peer or orderer will present a /metrics
resource
on the operations service.
When TLS is enabled, a valid client certificate is required to use this
service regardless of whether clientAuthRequired
is set to true
at the TLS level.
Peer¶
A peer can be configured to expose a /metrics
endpoint for Prometheus to
scrape by setting the metrics provider to prometheus
in the metrics
section
of core.yaml
.
metrics:
provider: prometheus
Orderer¶
An orderer can be configured to expose a /metrics
endpoint for Prometheus to
scrape by setting the metrics provider to prometheus
in the Metrics
section of orderer.yaml
.
Metrics:
Provider: prometheus
StatsD¶
StatsD is a simple statistics aggregation daemon. Metrics are sent to a
statsd
daemon where they are collected, aggregated, and pushed to a backend
for visualization and alerting. As this model requires instrumented processes
to send metrics data to StatsD, this is considered a push system.
Peer¶
A peer can be configured to send metrics to StatsD by setting the metrics
provider to statsd
in the metrics
section of core.yaml
. The statsd
subsection must also be configured with the address of the StatsD daemon, the
network type to use (tcp
or udp
), and how often to send the metrics. An
optional prefix
may be specified to help differentiate the source of the
metrics — for example, differentiating metrics coming from separate peers —
that would be prepended to all generated metrics.
metrics:
provider: statsd
statsd:
network: udp
address: 127.0.0.1:8125
writeInterval: 10s
prefix: peer-0
Orderer¶
An orderer can be configured to send metrics to StatsD by setting the metrics
provider to statsd
in the Metrics
section of orderer.yaml
. The Statsd
subsection must also be configured with the address of the StatsD daemon, the
network type to use (tcp
or udp
), and how often to send the metrics. An
optional prefix
may be specified to help differentiate the source of the
metrics.
Metrics:
Provider: statsd
Statsd:
Network: udp
Address: 127.0.0.1:8125
WriteInterval: 30s
Prefix: org-orderer
For a look at the different metrics that are generated, check out Metrics Reference.
Health Checks¶
The operations service provides a /healthz
resource that operators can use to
help determine the liveness and health of peers and orderers. The resource is
a conventional REST resource that supports GET requests. The implementation is
intended to be compatible with the liveness probe model used by Kubernetes but
can be used in other contexts.
When a GET /healthz
request is received, the operations service will call all
registered health checkers for the process to ensure all registered services and
dependencies are available. When all of the health checkers
return successfully, the operations service will respond with a 200 "OK"
and a
JSON body:
{
"status": "OK",
"time": "2009-11-10T23:00:00Z"
}
If one or more of the health checkers returns an error, the operations service
will respond with a 503 "Service Unavailable"
and a JSON body that includes
information about which health checker failed:
{
"status": "Service Unavailable",
"time": "2009-11-10T23:00:00Z",
"failed_checks": [
{
"component": "docker",
"reason": "failed to connect to Docker daemon: invalid endpoint"
}
]
}
The peer has the following health checks available:
Docker daemon health check (if a Docker endpoint is configured for chaincodes)
CouchDB health check (if CouchDB is configured as the state database)
When TLS is enabled, a valid client certificate is not required to use this
service unless clientAuthRequired
is set to true
.
Version¶
The orderer and peer both expose a /version
endpoint. This endpoint
serves a JSON document containing the orderer or peer version and the commit
SHA on which the release was created.
When TLS is enabled, a valid client certificate is not required to use this
service unless clientAuthRequired
is set to true
.