publishing history archives

If you want to run a Full Validator or an Archiver, you need to set up your node to publish a history archive. You can host an archive using a blob store such as Amazon's s3 or Digital Ocean's spaces, or you can simply serve a local archive directly via an HTTP server such as Nginx or Apache. If you're setting up a Watcher or a Basic Validator, you can skip this section. No matter what kind of node you're planning to run, make sure to set it up to get history, which is covered in Configuration.

Caching and History Archives

You can significantly reduce the data transfer costs associated with running a public History archive by using common caching techniques or a CDN.

Three simple rules apply to caching the History archives:

• Do not cache the archive state file .well-known/history-bantu.json ("Cache-Control: no-cache")

• Do not cache HTTP 4xx responses ("Cache-Control: no-cache")

• Cache everything else for as long as possible (> 1 day)

Local History Archive Using nginx

To publish a local history archive using nginx:

• Add a history configuration stanza to your /etc/bantu/bantu-core.cfg:

[HISTORY.local]
get="cp /mnt/xvdf/bantu-core-archive/node_001/{0} {1}"
put="cp {0} /mnt/xvdf/bantu-core-archive/node_001/{1}"
mkdir="mkdir -p /mnt/xvdf/bantu-core-archive/node_001/{0}"

• Run new-hist to create the local archive

# sudo -u bantu bantu-core --conf /etc/bantu/bantu-core.cfg new-hist local

This command creates the history archive structure:

# tree -a /mnt/xvdf/bantu-core-archive/
/mnt/xvdf/bantu-core-archive
└── node_001
    ├── history
    │   └── 00
    │       └── 00
    │           └── 00
    │               └── history-00000000.json
    └── .well-known
        └── bantu-history.json

6 directories, 2 files

• Configure a virtual host to serve the local archive (Nginx)

server {
  listen 80;
  root /mnt/xvdf/bantu-core-archive/node_001/;

  server_name history.example.com;

  # default is to deny all
  location / { deny all; }

  # do not cache 404 errors
  error_page 404 /404.html;
  location = /404.html {
    add_header Cache-Control "no-cache" always;
  }

  # do not cache history state file
  location ~ ^/.well-known/bantu-history.json$ {
    add_header Cache-Control "no-cache" always;
    try_files $uri;
  }

  # cache entire history archive for 1 day
  location / {
    add_header Cache-Control "max-age=86400";
    try_files $uri;
  }
}

Amazon S3 History Archive

To publish a history archive using Amazon S3:

• Add a history configuration stanza to your /etc/bantu/bantu-core.cfg:

[HISTORY.s3]
get='curl -sf http://history.example.com/{0} -o {1}' # Cached HTTP endpoint
put='aws s3 cp --region us-east-1 {0} s3://bucket.name/{1}' # Direct S3 access

• Run new-hist to create the s3 archive

# sudo -u bantu bantu-core --conf /etc/bantu/bantu-core.cfg new-hist s3

• Serve the archive using an Amazon S3 static site

• Optionally place a reverse proxy and CDN in front of the S3 static site

server {
  listen 80;
  root /srv/nginx/history.example.com;
  index index.html index.htm;

  server_name history.example.com;

  # use google nameservers for lookups
  resolver 8.8.8.8 8.8.4.4;

  # bucket.name s3 static site endpoint
  set $s3_bucket "bucket.name.s3-website-us-east-1.amazonaws.com";

  # default is to deny all
  location / { deny all; }

  # do not cache 404 errors
  error_page 404 /404.html;
  location = /404.html {
    add_header Cache-Control "no-cache" always;
  }

  # do not cache history state file
  location ~ ^/.well-known/bantu-history.json$ {
    add_header Cache-Control "no-cache" always;
    proxy_intercept_errors on;
    proxy_pass  http://$s3_bucket;
    proxy_read_timeout 120s;
    proxy_redirect off;
    proxy_buffering off;
    proxy_set_header        Host            $s3_bucket;
    proxy_set_header        X-Real-IP       $remote_addr;
    proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header        X-Forwarded-Proto $scheme;
  }

  # cache history archive for 1 day
  location / {
    add_header Cache-Control "max-age=86400";
    proxy_intercept_errors on;
    proxy_pass  http://$s3_bucket;
    proxy_read_timeout 120s;
    proxy_redirect off;
    proxy_buffering off;
    proxy_set_header        Host            $s3_bucket;
    proxy_set_header        X-Real-IP       $remote_addr;
    proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header        X-Forwarded-Proto $scheme;
  }
}

Backfilling a history archive

Given the choice, it's best to configure your history archive prior to your node's initial synch to the network. That way your validator's history publishes as you join/synch to the network.

However, if you have not published an archive during the node's initial synch, it's still possible to use the bantu-archivist command line tool to mirror, scan, and repair existing archives.

Using the BBF package repositories you can install bantu-archivist by running apt-get install bantu-archivist

The steps required to create a History archive for an existing validator — in other words, to upgrade a Basic Validator to a Full Validator — are straightforward:

• Stop your bantu-core instance (systemctl stop bantu-core)

• Configure a history archive for the new node

[HISTORY.local]
get="cp /mnt/xvdf/bantu-core-archive/node_001/{0} {1}"
put="cp {0} /mnt/xvdf/bantu-core-archive/node_001/{1}"
mkdir="mkdir -p /mnt/xvdf/bantu-core-archive/node_001/{0}"

• Run new-hist to create the local archive

# sudo -u bantu bantu-core --conf /etc/bantu/bantu-core.cfg new-hist local

This command creates the History archive structure:

# tree -a /mnt/xvdf/bantu-core-archive/
/mnt/xvdf/bantu-core-archive
└── node_001
    ├── history
    │   └── 00
    │       └── 00
    │           └── 00
    │               └── history-00000000.json
    └── .well-known
        └── bantu-history.json

6 directories, 2 file

• Start your bantu Core instance (systemctl start bantu-core)

• Allow your node to join the network and watch it start publishing a few checkpoints to the newly created archive

2019-04-25T12:30:43.275 GDUQJ [History INFO] Publishing 1 queued checkpoints [16895-16895]: Awaiting 0/0 prerequisites of: publish-000041ff

At this stage your validator is successfully publishing its history, which enables other users to join the network using your archive (although it won't allow them to CATCHUP_COMPLETE=true as the archive only has partial network history).

Complete History Archive

If you decide to publish a complete archive — which enables other users to join the network from the genesis ledger — it's also possible to use bantu-archivist to add all missing history data to your partial archive, and to verify the state and integrity of your archive. For example:

# bantu-archivist scan file:///mnt/xvdf/bantu-core-archive/node_001
2019/04/25 11:42:51 Scanning checkpoint files in range: [0x0000003f, 0x0000417f]
2019/04/25 11:42:51 Checkpoint files scanned with 324 errors
2019/04/25 11:42:51 Archive: 3 history, 2 ledger, 2 transactions, 2 results, 2 scp
2019/04/25 11:42:51 Scanning all buckets, and those referenced by range
2019/04/25 11:42:51 Archive: 30 buckets total, 30 referenced
2019/04/25 11:42:51 Examining checkpoint files for gaps
2019/04/25 11:42:51 Examining buckets referenced by checkpoints
2019/04/25 11:42:51 Missing history (260): [0x0000003f-0x000040ff]
2019/04/25 11:42:51 Missing ledger (260): [0x0000003f-0x000040ff]
2019/04/25 11:42:51 Missing transactions (260): [0x0000003f-0x000040ff]
2019/04/25 11:42:51 Missing results (260): [0x0000003f-0x000040ff]
2019/04/25 11:42:51 No missing buckets referenced in range [0x0000003f, 0x0000417f]
2019/04/25 11:42:51 324 errors scanning checkpoints

As you can tell from the output of the scan command, some history, ledger, transactions, and results are missing from the local history archive.

You can repair the missing data using bantu-archivist's repair command combined with a known full archive — such as the BBF public history archive:

# bantu-archivist repair http://history.bantu.org/prd/core-testnet/core_testnet_001/ file:///mnt/xvdf/bantu-core-archive/node_001/

2019/04/25 11:50:15 repairing http://history.bantu.org/prd/core-testnet/core_testnet_001/ -> file:///mnt/xvdf/bantu-core-archive/node_001/
2019/04/25 11:50:15 Starting scan for repair
2019/04/25 11:50:15 Scanning checkpoint files in range: [0x0000003f, 0x000041bf]
2019/04/25 11:50:15 Checkpoint files scanned with 244 errors
2019/04/25 11:50:15 Archive: 4 history, 3 ledger, 263 transactions, 61 results, 3 scp
2019/04/25 11:50:15 Error: 244 errors scanning checkpoints
2019/04/25 11:50:15 Examining checkpoint files for gaps
2019/04/25 11:50:15 Repairing history/00/00/00/history-0000003f.json
2019/04/25 11:50:15 Repairing history/00/00/00/history-0000007f.json
2019/04/25 11:50:15 Repairing history/00/00/00/history-000000bf.json
...
2019/04/25 11:50:22 Repairing ledger/00/00/00/ledger-0000003f.xdr.gz
2019/04/25 11:50:23 Repairing ledger/00/00/00/ledger-0000007f.xdr.gz
2019/04/25 11:50:23 Repairing ledger/00/00/00/ledger-000000bf.xdr.gz
...
2019/04/25 11:51:18 Repairing results/00/00/0e/results-00000ebf.xdr.gz
2019/04/25 11:51:18 Repairing results/00/00/0e/results-00000eff.xdr.gz
2019/04/25 11:51:19 Repairing results/00/00/0f/results-00000f3f.xdr.gz
...
2019/04/25 11:51:39 Repairing scp/00/00/00/scp-0000003f.xdr.gz
2019/04/25 11:51:39 Repairing scp/00/00/00/scp-0000007f.xdr.gz
2019/04/25 11:51:39 Repairing scp/00/00/00/scp-000000bf.xdr.gz
...
2019/04/25 11:51:50 Re-running checkpoing-file scan, for bucket repair
2019/04/25 11:51:50 Scanning checkpoint files in range: [0x0000003f, 0x000041bf]
2019/04/25 11:51:50 Checkpoint files scanned with 5 errors
2019/04/25 11:51:50 Archive: 264 history, 263 ledger, 263 transactions, 263 results, 241 scp
2019/04/25 11:51:50 Error: 5 errors scanning checkpoints
2019/04/25 11:51:50 Scanning all buckets, and those referenced by range
2019/04/25 11:51:50 Archive: 40 buckets total, 2478 referenced
2019/04/25 11:51:50 Examining buckets referenced by checkpoints
2019/04/25 11:51:50 Repairing bucket/57/18/d4/bucket-5718d412bdc19084dafeb7e1852cf06f454392df627e1ec056c8b756263a47f1.xdr.gz
2019/04/25 11:51:50 Repairing bucket/8a/a1/62/bucket-8aa1624cc44aa02609366fe6038ffc5309698d4ba8212ef9c0d89dc1f2c73033.xdr.gz
2019/04/25 11:51:50 Repairing bucket/30/82/6a/bucket-30826a8569cb6b178526ddba71b995c612128439f090f371b6bf70fe8cf7ec24.xdr.gz
...

A final scan of the local archive confirms that it has been successfully repaired

# bantu-archivist scan file:///mnt/xvdf/bantu-core-archive/node_001

2019/04/25 12:15:41 Scanning checkpoint files in range: [0x0000003f, 0x000041bf]
2019/04/25 12:15:41 Archive: 264 history, 263 ledger, 263 transactions, 263 results, 241 scp
2019/04/25 12:15:41 Scanning all buckets, and those referenced by range
2019/04/25 12:15:41 Archive: 2478 buckets total, 2478 referenced
2019/04/25 12:15:41 Examining checkpoint files for gaps
2019/04/25 12:15:41 Examining buckets referenced by checkpoints
2019/04/25 12:15:41 No checkpoint files missing in range [0x0000003f, 0x000041bf]
2019/04/25 12:15:41 No missing buckets referenced in range [0x0000003f, 0x000041bf]

Start your bantu-core instance (systemctl start bantu-core), and you should have a complete history archive being written to by your full validator.