1OC(1) June 2016 OC(1)
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6 oc types - An introduction to concepts and types
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11 oc types [OPTIONS]
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16 Concepts and Types
17 Kubernetes and OpenShift help developers and operators build, test, and
20 deploy applications in a containerized cloud environment. Applications
21 may be composed of all of the components below, although most develop‐
22 ers will be concerned with Services, Deployments, and Builds for deliv‐
23 ering changes.
24 Concepts:
27 ·
29 Containers: A definition of how to run one or more processes inside of
31 a portable Linux environment. Containers are started from an Image and
32 are usually isolated from other containers on the same machine.
33 ·
35 Image: A layered Linux filesystem that contains application code,
37 dependencies, and any supporting operating system libraries. An image
38 is identified by a name that can be local to the current cluster or
39 point to a remote Docker registry (a storage server for images).
40 ·
42 Pods [pod]: A set of one or more containers that are deployed onto a
44 Node together and share a unique IP and Volumes (persistent storage).
45 Pods also define the security and runtime policy for each container.
46 ·
48 Labels: Labels are key value pairs that can be assigned to any resource
50 in the system for grouping and selection. Many resources use labels to
51 identify sets of other resources.
52 ·
54 Volumes: Containers are not persistent by default - on restart their
56 contents are cleared. Volumes are mounted filesystems available to Pods
57 and their containers which may be backed by a number of host-local or
58 network attached storage endpoints. The simplest volume type is Empty‐
59 Dir, which is a temporary directory on a single machine. Administrators
60 may also allow you to request a Persistent Volume that is automatically
61 attached to your pods.
62 ·
64 Nodes [node]: Machines set up in the cluster to run containers. Usually
66 managed by administrators and not by end users.
67 ·
69 Services [svc]: A name representing a set of pods (or external servers)
71 that are accessed by other pods. The service gets an IP and a DNS name,
72 and can be exposed externally to the cluster via a port or a Route.
73 It's also easy to consume services from pods because an environment
74 variable with the name <SERVICE>_HOST is automatically injected into
75 other pods.
76 ·
78 Routes [route]: A route is an external DNS entry (either a top level
80 domain or a dynamically allocated name) that is created to point to a
81 service so that it can be accessed outside the cluster. The administra‐
82 tor may configure one or more Routers to handle those routes, typically
83 through an Apache or HAProxy load balancer / proxy.
84 ·
86 Replication Controllers [rc]: A replication controller maintains a spe‐
88 cific number of pods based on a template that match a set of labels. If
89 pods are deleted (because the node they run on is taken out of service)
90 the controller creates a new copy of that pod. A replication controller
91 is most commonly used to represent a single deployment of part of an
92 application based on a built image.
93 ·
95 Deployment Configuration [dc]: Defines the template for a pod and man‐
97 ages deploying new images or configuration changes whenever those
98 change. A single deployment configuration is usually analogous to a
99 single micro-service. Can support many different deployment patterns,
100 including full restart, customizable rolling updates, and fully custom
101 behaviors, as well as pre- and post- hooks. Each deployment is repre‐
102 sented as a replication controller.
103 ·
105 Build Configuration [bc]: Contains a description of how to build source
107 code and a base image into a new image - the primary method for deliv‐
108 ering changes to your application. Builds can be source based and use
109 builder images for common languages like Java, PHP, Ruby, or Python, or
110 be Docker based and create builds from a Dockerfile. Each build config‐
111 uration has web-hooks and can be triggered automatically by changes to
112 their base images.
113 ·
115 Builds [build]: Builds create a new image from source code, other
117 images, Dockerfiles, or binary input. A build is run inside of a con‐
118 tainer and has the same restrictions normal pods have. A build usually
119 results in an image pushed to a Docker registry, but you can also
120 choose to run a post-build test that does not push an image.
121 ·
123 Image Streams and Image Stream Tags [is,istag]: An image stream groups
125 sets of related images under tags - analogous to a branch in a source
126 code repository. Each image stream may have one or more tags (the
127 default tag is called "latest") and those tags may point at external
128 Docker registries, at other tags in the same stream, or be controlled
129 to directly point at known images. In addition, images can be pushed to
130 an image stream tag directly via the integrated Docker registry.
131 ·
133 Secrets [secret]: The secret resource can hold text or binary secrets
135 for delivery into your pods. By default, every container is given a
136 single secret which contains a token for accessing the API (with lim‐
137 ited privileges) at /var/run/secrets/kubernetes.io/serviceaccount. You
138 can create new secrets and mount them in your own pods, as well as ref‐
139 erence secrets from builds (for connecting to remote servers) or use
140 them to import remote images into an image stream.
141 ·
143 Projects [project]: All of the above resources (except Nodes) exist
145 inside of a project. Projects have a list of members and their roles,
146 like viewer, editor, or admin, as well as a set of security controls on
147 the running pods, and limits on how many resources the project can use.
148 The names of each resource are unique within a project. Developers may
149 request projects be created, but administrators control the resources
150 allocated to projects.
151 For more, see ⟨https://docs.openshift.com⟩
153
157 --allow_verification_with_non_compliant_keys=false
158 Allow a SignatureVerifier to use keys which are technically
159 non-compliant with RFC6962.
160 --alsologtostderr=false
163 log to standard error as well as files
164 --application_metrics_count_limit=100
167 Max number of application metrics to store (per container)
168 --as=""
171 Username to impersonate for the operation
172 --as-group=[]
175 Group to impersonate for the operation, this flag can be repeated
176 to specify multiple groups.
177 --azure-container-registry-config=""
180 Path to the file containing Azure container registry configuration
181 information.
182 --boot_id_file="/proc/sys/kernel/random/boot_id"
185 Comma-separated list of files to check for boot-id. Use the first
186 one that exists.
187 --cache-dir="/builddir/.kube/http-cache"
190 Default HTTP cache directory
191 --certificate-authority=""
194 Path to a cert file for the certificate authority
195 --client-certificate=""
198 Path to a client certificate file for TLS
199 --client-key=""
202 Path to a client key file for TLS
203 --cloud-provider-gce-lb-src-cidrs=130.211.0.0/22,209.85.152.0/22,209.85.204.0/22,35.191.0.0/16
206 CIDRs opened in GCE firewall for LB traffic proxy health checks
207 --cluster=""
210 The name of the kubeconfig cluster to use
211 --container_hints="/etc/cadvisor/container_hints.json"
214 location of the container hints file
215 --containerd="unix:///var/run/containerd.sock"
218 containerd endpoint
219 --context=""
222 The name of the kubeconfig context to use
223 --default-not-ready-toleration-seconds=300
226 Indicates the tolerationSeconds of the toleration for
227 notReady:NoExecute that is added by default to every pod that does not
228 already have such a toleration.
229 --default-unreachable-toleration-seconds=300
232 Indicates the tolerationSeconds of the toleration for unreach‐
233 able:NoExecute that is added by default to every pod that does not
234 already have such a toleration.
235 --docker="unix:///var/run/docker.sock"
238 docker endpoint
239 --docker-tls=false
242 use TLS to connect to docker
243 --docker-tls-ca="ca.pem"
246 path to trusted CA
247 --docker-tls-cert="cert.pem"
250 path to client certificate
251 --docker-tls-key="key.pem"
254 path to private key
255 --docker_env_metadata_whitelist=""
258 a comma-separated list of environment variable keys that needs to
259 be collected for docker containers
260 --docker_only=false
263 Only report docker containers in addition to root stats
264 --docker_root="/var/lib/docker"
267 DEPRECATED: docker root is read from docker info (this is a fall‐
268 back, default: /var/lib/docker)
269 --enable_load_reader=false
272 Whether to enable cpu load reader
273 --event_storage_age_limit="default=24h"
276 Max length of time for which to store events (per type). Value is a
277 comma separated list of key values, where the keys are event types
278 (e.g.: creation, oom) or "default" and the value is a duration. Default
279 is applied to all non-specified event types
280 --event_storage_event_limit="default=100000"
283 Max number of events to store (per type). Value is a comma sepa‐
284 rated list of key values, where the keys are event types (e.g.: cre‐
285 ation, oom) or "default" and the value is an integer. Default is
286 applied to all non-specified event types
287 --global_housekeeping_interval=0
290 Interval between global housekeepings
291 --housekeeping_interval=0
294 Interval between container housekeepings
295 --insecure-skip-tls-verify=false
298 If true, the server's certificate will not be checked for validity.
299 This will make your HTTPS connections insecure
300 --kubeconfig=""
303 Path to the kubeconfig file to use for CLI requests.
304 --log-flush-frequency=0
307 Maximum number of seconds between log flushes
308 --log_backtrace_at=:0
311 when logging hits line file:N, emit a stack trace
312 --log_cadvisor_usage=false
315 Whether to log the usage of the cAdvisor container
316 --log_dir=""
319 If non-empty, write log files in this directory
320 --logtostderr=true
323 log to standard error instead of files
324 --machine_id_file="/etc/machine-id,/var/lib/dbus/machine-id"
327 Comma-separated list of files to check for machine-id. Use the
328 first one that exists.
329 --match-server-version=false
332 Require server version to match client version
333 -n, --namespace=""
336 If present, the namespace scope for this CLI request
337 --request-timeout="0"
340 The length of time to wait before giving up on a single server
341 request. Non-zero values should contain a corresponding time unit (e.g.
342 1s, 2m, 3h). A value of zero means don't timeout requests.
343 -s, --server=""
346 The address and port of the Kubernetes API server
347 --stderrthreshold=2
350 logs at or above this threshold go to stderr
351 --storage_driver_buffer_duration=0
354 Writes in the storage driver will be buffered for this duration,
355 and committed to the non memory backends as a single transaction
356 --storage_driver_db="cadvisor"
359 database name
360 --storage_driver_host="localhost:8086"
363 database host:port
364 --storage_driver_password="root"
367 database password
368 --storage_driver_secure=false
371 use secure connection with database
372 --storage_driver_table="stats"
375 table name
376 --storage_driver_user="root"
379 database username
380 --token=""
383 Bearer token for authentication to the API server
384 --user=""
387 The name of the kubeconfig user to use
388 -v, --v=0
391 log level for V logs
392 --version=false
395 Print version information and quit
396 --vmodule=
399 comma-separated list of pattern=N settings for file-filtered log‐
400 ging
401
405 # View all projects you have access to
406 oc get projects
407 # See a list of all services in the current project
409 oc get svc
410 # Describe a deployment configuration in detail
412 oc describe dc mydeploymentconfig
413 # Show the images tagged into an image stream
415 oc describe is ruby-centos7
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421 oc(1),
422
426 June 2016, Ported from the Kubernetes man-doc generator
427Openshift Openshift CLI User Manuals OC(1)