Internet Calendars are calendars that you publish to an Internet site, where others can view it or subscribe to it. Internet Calendars use the iCalendar format and the .ics file name extension.
You can share one-time static calendars, known as Calendar Snapshots, in an email message. Or you can publish calendars to a special web server designed to host calendars in the iCalendar format. The benefit of the latter is that when you change the calendar in Outlook, the changes are synchronized to the web server. This enables those who use an Internet Calendar subscription to see the latest information automatically.
Why publish Internet Calendars?
Internet Calendars let you share calendar and availability information with other people. For example, you can publish your soccer team’s practice schedule. Each player can subscribe to the published calendar and then see any updates that you make to the calendar. Other people might choose to view the Internet Calendar subscription in a web browser, Outlook, or another application.
How to publish Internet Calendars
You can share your Outlook calendar with others by publishing it from Outlook on the web.
To share your Outlook calendar on Outlook.com, first save it as an iCalendar (.ics file), import it into Outlook.com, then share it with the people who need to see it.
Under the settings in Outlook on the web, go to Calendar > Shared calendars. Choose the calendar you wish to publish and the level of details that you want others to see.
Note: Published calendars are viewable by anyone with the link to the calendar.
A snapshot is a backup of a running Elasticsearch cluster. You can use snapshots to:
- Regularly back up a cluster with no downtime
- Recover data after deletion or a hardware failure
- Transfer data between clusters
- Reduce your storage costs by using searchable snapshots in the cold and frozen data tiers
The snapshot workflowedit
Elasticsearch stores snapshots in an off-cluster storage location called a snapshot repository. Before you can take or restore snapshots, you must register a snapshot repository on the cluster. Elasticsearch supports several repository types with cloud storage options, including:
- AWS S3
- Google Cloud Storage (GCS)
- Microsoft Azure
After you register a snapshot repository, you can use snapshot lifecycle management (SLM) to automatically take and manage snapshots. You can then restore a snapshot to recover or transfer its data.
By default, a snapshot of a cluster contains the cluster state, all data streams, and all open indices, including system indices. The cluster state includes:
- Persistent cluster settings
- Index templates
- Legacy index templates
- Ingest pipelines
- ILM policies
- For snapshots taken after 7.12.0, feature states
You can also take snapshots of only specific data streams or indices in the cluster. A snapshot that includes a data stream or index automatically includes its aliases. When you restore a snapshot, you can choose whether to restore these aliases.
Snapshots don’t contain or back up:
- Transient cluster settings
- Registered snapshot repositories
- Node configuration files
A feature state contains the indices and data streams used to store configurations, history, and other data for an Elastic feature, such as Elasticsearch security or Kibana.
A feature state typically includes one or more system indices or system data streams. It may also include regular indices and data streams used by the feature. For example, a feature state may include a regular index that contains the feature’s execution history. Storing this history in a regular index lets you more easily search it.
How snapshots workedit
Snapshots are automatically deduplicated to save storage space and reduce network transfer costs. To back up an index, a snapshot makes a copy of the index’s segments and stores them in the snapshot repository. Since segments are immutable, the snapshot only needs to copy any new segments created since the repository’s last snapshot.
Each snapshot is also logically independent. When you delete a snapshot, Elasticsearch only deletes the segments used exclusively by that snapshot. Elasticsearch doesn’t delete segments used by other snapshots in the repository.
Snapshots and shard allocationedit
A snapshot copies segments from an index’s primary shards. When you start a snapshot, Elasticsearch immediately starts copying the segments of any available primary shards. If a shard is starting or relocating, Elasticsearch will wait for these processes to complete before copying the shard’s segments. If one or more primary shards aren’t available, the snapshot attempt fails.
Once a snapshot begins copying a shard’s segments, Elasticsearch won’t move the shard to another node, even if rebalancing or shard allocation settings would typically trigger reallocation. Elasticsearch will only move the shard after the snapshot finishes copying the shard’s data.
Snapshot start and stop timesedit
A snapshot doesn’t represent a cluster at a precise point in time. Instead, each snapshot includes a start and end time. The snapshot represents a view of each shard’s data at some point between these two times.
To restore a snapshot to a cluster, the versions for the snapshot, cluster, and any restored indices must be compatible.
Snapshot version compatibilityedit
You can’t restore a snapshot to an earlier version of Elasticsearch. For example, you can’t restore a snapshot taken in 7.6.0 to a cluster running 7.5.0.
Any index you restore from a snapshot must also be compatible with the current cluster’s version. If you try to restore an index created in an incompatible version, the restore attempt will fail.
Index creation version
You can’t restore an index to an earlier version of Elasticsearch. For example, you can’t restore an index created in 7.6.0 to a cluster running 7.5.0.
A compatible snapshot can contain indices created in an incompatible version. For example, a snapshot of a 6.8 cluster can contain an index created in 5.6. If you try to restore the 5.6 index to a 7.16 cluster, the restore attempt will fail. Keep this in mind if you take a snapshot before upgrading a cluster.
As a workaround, you can first restore the index to another cluster running the latest version of Elasticsearch that’s compatible with both the index and your current cluster. You can then use reindex-from-remote to rebuild the index on your current cluster. Reindex from remote is only possible if the index’s _source is enabled.
Reindexing from remote can take significantly longer than restoring a snapshot. Before you start, test the reindex from remote process with a subset of the data to estimate your time requirements.
Other backup methodsedit
Taking a snapshot is the only reliable and supported way to back up a cluster. You cannot back up an Elasticsearch cluster by making copies of the data directories of its nodes. There are no supported methods to restore any data from a filesystem-level backup. If you try to restore a cluster from such a backup, it may fail with reports of corruption or missing files or other data inconsistencies, or it may appear to have succeeded having silently lost some of your data.
A copy of the data directories of a cluster’s nodes does not work as a backup because it is not a consistent representation of their contents at a single point in time. You cannot fix this by shutting down nodes while making the copies, nor by taking atomic filesystem-level snapshots, because Elasticsearch has consistency requirements that span the whole cluster. You must use the built-in snapshot functionality for cluster backups.
Don’t modify anything within the repository or run processes that might interfere with its contents. If something other than Elasticsearch modifies the contents of the repository then future snapshot or restore operations may fail, reporting corruption or other data inconsistencies, or may appear to succeed having silently lost some of your data.
You may however safely restore a repository from a backup as long as
- Canvas Admin
- Canvas Admin Discussion
- Canvas Calendar Feeds Not Updating
Our school has found multiple applications for the calendar feeds (ics link) available on the Calendar page. We’ve noticed that sometimes changes made to events in Canvas aren’t reflected in the feed. I spoke with Canvas Tech Support and my understanding is that they are making the information available so the problem has to be elsewhere. Their suggestion was to have our users delete then re-add the link whenever something on the calendar changes. That is impractical so I am continuing to look for the root cause and/or a way to fix this.
Does anyone happen to have any experience with calendar feeds not updating?
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@msanders , I want to see if I’m understanding this correctly. Users are copying their Canvas calendar feed and using that with another calendar services. Did I get that right? We’re a small community college without a ton of calendar use. That being said, I’m not aware of any known issues with the calendar feed not communicating the updated information to the external calendar service. When you say, “We’ve noticed that sometimes changes made to events in Canvas aren’t reflected in the feed ” are you looking at the feed itself, or the results in the connected external calendar service? There is also a matter of timing and I recall coming across some posts here in the past about the time it takes to update. Here’s an example: https://community.canvaslms.com/message/4503
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Thank you for the information! The other links are helpful. Do you have a recommended method for subscribing to a Canvas calendar in Outlook? I think this may be related to the problems we are experiencing.
Here is one example of what we have tried to do. I created a “winter sports user” in Canvas and enrolled that user as an observer in all of the winter sports courses. I then logged into Canvas as that user and copied the https://xyz123.ics link from the calendar page. I emailed the link to myself and a handful of other test users. Those users and I then subscribed to the “winter sports user” Canvas calendar in Outlook. We found multiple ways to subscribe/add an external calendar to Outlook. Regardless of how the ics file was added/subscribed, all users could initially see all of the events in the Outlook client calendar. However, if we later changed an event in Canvas, some users could see the updated event in Outlook, but other users continued to see the original event (even after 24+ hours). If the users with the “static” calendars deleted the winter sports calendar link in Outlook then re-added it, then the updated event was displayed.
I’ve tried repeating the test described above to see which method worked every time and couldn’t find one. I am (clearly) new to using Internet Calendars so I feel like I’m just overlooking something obvious. Any recommendations on how to subscribe to a Canvas ics file/link from Outlook (2016) and have the Outlook calendar dynamically update when events are changed in Canvas would be greatly appreciated!