github/kubernetes
1
0
Fork 0
mirror of https://github.com/k3s-io/kubernetes.git synced 2025-09-16 06:32:32 +00:00
Code Issues Projects Releases Wiki Activity

docs: make markdown less GitHub-specific

Browse Source 
- add newline before lists
- use ‘*’ for lists instead of ‘-’; use 4 spaces to indent nested list
This commit is contained in:
Thien-Thi Nguyen
2015-06-17 17:59:05 +02:00
parent d8e5225144
commit 1647e12c4e
2 changed files with 19 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
docs/volumes.md
View File

@@ -20,8 +20,9 @@ Selected volume types are described below.
An EmptyDir volume is created when a Pod is bound to a Node. It is initially empty, when the first Container command starts. Containers in the same pod can all read and write the same files in the EmptyDir volume. When a Pod is unbound, the data in the EmptyDir is deleted forever.
Some uses for an EmptyDir are:
- scratch space, such as for a disk-based mergesort or checkpointing a long computation,
- a directory that a content-manager container fills with data while a webserver container serves the data.
* scratch space, such as for a disk-based mergesort or checkpointing a long computation,
* a directory that a content-manager container fills with data while a webserver container serves the data.
Currently, the user cannot control what kind of media is used for an EmptyDir (see also the section _Resources_, below). If the Kubelet is configured to use a disk drive, then all EmptyDir volumes will be created on that disk drive. In the future, it is expected that Pods can control whether the EmptyDir is on a disk drive, SSD, or tmpfs.
@@ -29,12 +30,14 @@ Currently, the user cannot control what kind of media is used for an EmptyDir (s
A Volume with a HostPath property allows access to files on the current node.
Some uses for a HostPath are:
- running a container that needs access to Docker internals; use a HostPath of /var/lib/docker.
- running cAdvisor in a container; use a HostPath of /dev/cgroups.
* running a container that needs access to Docker internals; use a HostPath of /var/lib/docker.
* running cAdvisor in a container; use a HostPath of /dev/cgroups.
Watch out when using this type of volume, because:
- pods with identical configuration (such as created from a podTemplate) may behave differently on different nodes due to different files on different nodes.
- When Kubernetes adds resource-aware scheduling, as is planned, it will not be able to account for resources used by a HostPath.
* pods with identical configuration (such as created from a podTemplate) may behave differently on different nodes due to different files on different nodes.
* When Kubernetes adds resource-aware scheduling, as is planned, it will not be able to account for resources used by a HostPath.
### GCEPersistentDisk
__Important: You must create a PD using ```gcloud``` or the GCE API before you can use it__
@@ -43,12 +46,13 @@ A Volume with a GCEPersistentDisk property allows access to files on a Google Co
[Persistent Disk](http://cloud.google.com/compute/docs/disks).
There are some restrictions when using a GCEPersistentDisk:
- the nodes (what the kubelet runs on) need to be GCE VMs
- those VMs need to be in the same GCE project and zone as the PD
- avoid creating multiple pods that use the same Volume if any mount it read/write.
- if a pod P already mounts a volume read/write, and a second pod Q attempts to use the volume, regardless of if it tries to use it read-only or read/write, Q will fail.
- if a pod P already mounts a volume read-only, and a second pod Q attempts to use the volume read/write, Q will fail.
- replication controllers with replicas > 1 can only be created for pods that use read-only mounts.
* the nodes (what the kubelet runs on) need to be GCE VMs
* those VMs need to be in the same GCE project and zone as the PD
* avoid creating multiple pods that use the same Volume if any mount it read/write.
* if a pod P already mounts a volume read/write, and a second pod Q attempts to use the volume, regardless of if it tries to use it read-only or read/write, Q will fail.
* if a pod P already mounts a volume read-only, and a second pod Q attempts to use the volume read/write, Q will fail.
* replication controllers with replicas > 1 can only be created for pods that use read-only mounts.
#### Creating a PD
Before you can use a GCE PD with a pod, you need to create it.