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adequate understanding of the remote OS are encouraged to prepare and |
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inject all kinds of useful files, e.g., **lists of package sources**, |
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**default user profiles**, **device mount configurations**, etc. |
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Clusters of virtual servers |
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--------------------------- |
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A cluster of virtual servers can be created and deleted using special |
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arguments. |
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A convention is necessary: all servers belonging to the same cluster will have |
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names with a common prefix e.g., *cluster1*, *cluster2*, etc. This prefix |
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acts as the cluster name or the cluster key. Still, users must be careful not to |
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confuse cluster servers with other servers that coincidentally have the same |
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prefix (e.g., *cluster_of_stars*). |
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First, let's create a cluster of 4 servers. Each server will run the image with |
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id *f1r57-1m4g3-1d* on the hardware specified by the flavor with id *1*. The |
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prefix of the cluster will be "my cluster " |
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.. code-block:: console |
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$ kamaki |
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[kamaki]: server |
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[server]: create "my cluster " 1 f1r57-1m4g3-1d --cluster-size=4 --wait |
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... <omitted for clarity> |
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adminPass: S0mePassw0rd0n3 |
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created: 2013-06-19T12:34:49.362078+00:00 |
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flavor: |
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id: 1 |
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id: 322 |
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image: |
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id: f1r57-1m4g3-1d |
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name: my cluster 1 |
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[progress bar waiting server to build] |
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Server 321: status is now ACTIVE |
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... <omitted for clarity> |
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adminPass: S0mePassw0rdTwo |
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created: 2013-06-19T12:34:47.362078+00:00 |
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flavor: |
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id: 1 |
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id: 321 |
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image: |
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id: f1r57-1m4g3-1d |
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name: my cluster 2 |
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[progress bar waiting server to build] |
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Server 322: status is now ACTIVE |
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... <omitted for clarity> |
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adminPass: S0mePassw0rdThree |
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created: 2013-06-19T12:34:55.362078+00:00 |
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flavor: |
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id: 1 |
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id: 323 |
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image: |
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id: f1r57-1m4g3-1d |
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name: my cluster 3 |
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[progress bar waiting server to build] |
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Server 323: status is now ACTIVE |
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... <omitted for clarity> |
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adminPass: S0mePassw0rdFour |
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created: 2013-06-19T12:34:59.362078+00:00 |
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flavor: |
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id: 1 |
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id: 324 |
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image: |
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id: f1r57-1m4g3-1d |
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name: my cluster 4 |
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[progress bar waiting server to build] |
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Server 324: status is now ACTIVE |
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.. note:: The creation dates are similar but not ordered. This is because the |
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servers are created asynchronously. To deactivate asynchronous operations |
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in kamaki, set max_theads to 1 |
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.. code-block:: console |
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# Deactivate multithreading |
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[server]: /config set max_theads 1 |
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.. note:: the *- - wait* argument is optional, but if not used, the *create* |
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call will terminate as long as the servers are spawned, even if they are |
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not built yet. |
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.. warning:: The server details (password, etc.) are printed in |
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**standard output** while the progress bar and notification messages are |
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printed in **standard error** |
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Now, let's see our clusters: |
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.. code-block:: console |
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[server]: list --name-prefix "my cluster " |
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321 my cluster 2 |
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322 my cluster 1 |
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323 my cluster 3 |
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324 my cluster 4 |
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For demonstration purposes, let's suppose that the maximum resource limit is |
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reached if we create 2 more servers. We will attempt to expand "my cluster" by |
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4 servers, expecting kamaki to raise a quota-related error. |
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.. code-block:: console |
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$ kamaki |
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[kamaki]: server |
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[server]: create "my cluster " 1 f1r57-1m4g3-1d --cluster-size=4 --wait |
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Failed to build 4 servers |
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Found 2 matching servers: |
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325 my cluster 1 |
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326 my cluster 2 |
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Check if any of these servers should be removed |
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(413) REQUEST ENTITY TOO LARGE overLimit (Resource Limit Exceeded for your |
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account.) |
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| Limit for resource 'Virtual Machine' exceeded for your account. |
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Available: 0, Requested: 1 |
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The cluster expansion has failed, but 2 of the attempted 4 servers are being |
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created right now. It's up to the users judgment to destroy them or keep them. |
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First, we need to list all servers: |
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.. code-block:: console |
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[server] list --name-prefix="my cluster " |
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321 my cluster 2 |
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322 my cluster 1 |
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323 my cluster 3 |
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324 my cluster 4 |
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325 my cluster 1 |
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326 my cluster 2 |
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.. warning:: Kamaki will always create clusters by attaching an increment at |
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the right of the prefix. The increments always start from 1. |
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Now, our cluster seems messed up. Let's destroy it and rebuilt it. |
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.. code-block:: console |
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[server]: delete "my cluster " --cluster --wait |
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[progress bar waiting server to be deleted] |
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Server 321: status is now DELETED |
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[progress bar waiting server to be deleted] |
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Server 322: status is now DELETED |
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[progress bar waiting server to be deleted] |
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Server 323: status is now DELETED |
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[progress bar waiting server to be deleted] |
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Server 324: status is now DELETED |
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[progress bar waiting server to be deleted] |
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Server 325: status is now DELETED |
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[progress bar waiting server to be deleted] |
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Server 326: status is now DELETED |
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.. note:: *delete* performs a single deletion if feeded with a server id, but |
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it performs a mass deletion, based on the name, if called with --cluster |
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While creating the first cluster, we had to note down all passwords |
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The passwords for each server are printed on the console while creating them. |
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It would be far more convenient, though, if we could massively inject an ssh |
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key into all of them. Let's do that! |
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.. code-block:: console |
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[server]: create "my new cluster " 1 f1r57-1m4g3-1d --cluster-size=4 --wait --personality /home/someuser/.ssh/id_rsa.pub,/root/.ssh/authorized_keys,root,root,0777 |
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... <output omitted for clarity> |
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Now, let's check if the cluster has been created. |
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.. code-block:: console |
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[server]: list --name-prefix="my new cluster " |
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321 my new cluster 1 |
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322 my new cluster 2 |
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323 my new cluster 3 |
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324 my new cluster 4 |
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We now have a cluster of 4 virtual servers and we can ssh in all of them |
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without a password. |
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Here is a bash script for creating clusters: |
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.. code-block:: bash |
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#!/bin/bash |
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CL_PREFIX="cluster" |
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CL_SIZE=4 |
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PUB_KEYS="${HOME}/.ssh/id_rsa.pub" |
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OUT="cl_servers.txt" |
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CLOUD=`kamaki config get default_cloud` |
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FLAVOR_ID=1 |
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IMAGE_ID="f1r57-1m4g3-1d" |
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echo "Clean up cluster \"${CL_PREFIX}\"" |
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kamaki --cloud=${CLOUD} server delete ${CL_PREFIX} --cluster --wait |
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echo "Cluster \"${CL_PREFIX}\"" > ${OUT} |
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echo "Create cluster \"${CL_PREFIX}\" of size ${CL_SIZE}" |
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kamaki --cloud=${CLOUD} server create ${CL_PREFIX} ${FLAVOR_ID} ${IMAGE_ID} |
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--cluster-size=${CL_SIZE} --wait |
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--personality ${PUB_KEYS},/root/.ssh/authorized_keys,root,root >>${OUT} |
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echo "A list of created servers can be found at ${OUT}" |
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